System for cardiac procedures

ABSTRACT

A system for accessing a patient&#39;s cardiac anatomy which includes an endovascular aortic partitioning device that separates the coronary arteries and the heart from the rest of the patient&#39;s arterial system. The endovascular device for partitioning a patient&#39;s ascending aorta comprises a flexible shaft having a distal end, a proximal end, and a first inner lumen therebetween with an opening at the distal end. The shaft may have a preshaped distal portion with a curvature generally corresponding to the curvature of the patient&#39;s aortic arch. An expandable means, e.g. a balloon, is disposed near the distal end of the shaft proximal to the opening in the first inner lumen for occluding the ascending aorta so as to block substantially all blood flow therethrough for a plurality of cardiac cycles, while the patient is supported by cardiopulmonary bypass. The endovascular aortic partitioning device may be coupled to an arterial bypass cannula for delivering oxygenated blood to the patient&#39;s arterial system. The heart muscle or myocardium is paralyzed by the retrograde delivery of a cardioplegic fluid to the myocardium through patient&#39;s coronary sinus and coronary veins, or by antegrade delivery of cardioplegic fluid through a lumen in the endovascular aortic partitioning device to infuse cardioplegic fluid into the coronary arteries. The pulmonary trunk may be vented by withdrawing liquid from the trunk through an inner lumen of an elongated catheter. The cardiac accessing system is particularly suitable for removing the aortic valve and replacing the removed valve with a prosthetic valve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 09/167,912filed Oct. 7, 1998, now abandoned which is a continuation of applicationSer. No. 08/819,455, filed Mar. 17, 1997, now U.S. Pat. No. 5,868,702which is a file wrapper continuation of application Ser. No. 08/453,426filed May 30, 1995, now U.S. Pat. No. 5,885,238 which is a divisional ofapplication Ser. No. 08/282,192, filed Jul. 28, 1994 now issued as U.S.Pat. No. 5,584,803, which is a continuation-in-part of Ser. No.08/162,742, filed Dec. 3, 1993 now abandoned, which is acontinuation-in-part of application Ser. No. 08/123,411 filed Sep. 17,1993 now abandoned, which is a continuation-in-part of application Ser.No. 07/991,188 filed Dec. 15, 1992 now abandoned, which is acontinuatiion-in-part of application Ser. No. 07/730,559 filed Jul. 16,1991 now U.S. Pat. No. 5,370,685 and said Ser. No. 09/167,912, filedOct. 7, 1998. This application is also a continuation-in-part of U.S.patent application Ser. No. 08/159,815, filed Nov. 30, 1993 now U.S.Pat. No. 5,433,700, which is a U.S. counterpart of Australian PatentApplication No. PL 6170, filed Dec. 3, 1992. The complete disclosures ofall the formentioned related to U.S. patent applications are herebyincorporated herein by reference for all purposes.

FIELD OF THE INVENTION

This invention relates generally to devices and methods for performingcardiovascular, pulmonary and neurosurgical procedures wherein thepatient is placed on cardiopulmonary bypass. More specifically, theinvention relates to devices and methods for isolating the heart andcoronary blood vessels from the remainder of the arterial system, tofacilitate arresting the heart and establishing cardiopulmonary bypass.This invention also relates to methods and systems for performingminimally-invasive cardiac procedures such as the endovascular placementof or removal and replacement of heart valves.

BACKGROUND OF THE INVENTION

Various cardiovascular, neurosurgical, pulmonary and otherinterventional procedures, including repair or replacement of aortic,mitral and other heart valves, repair of septal defects, pulmonarythrombectomy, coronary artery bypass grafting, angioplasty, atherectomy,treatment of aneurysms, electrophysiological mapping and ablation, andneurovascular procedures, may require general anesthesia,cardiopulmonary bypass, and arrest of cardiac function. In suchprocedures, the heart and coronary blood vessels must be isolated fromthe remainder of the circulatory system. This serves several purposes.First, such isolation facilitates infusion of cardioplegic fluid intothe coronary arteries in order to perfuse the myocardium and therebyarrest cardiac function, without allowing the cardioplegic fluid to bedistributed elsewhere in the patient's circulatory system. Second, suchisolation facilitates the use of a cardiopulmonary bypass system tomaintain circulation of oxygenated blood throughout the circulatorysystem while the heart is stopped, without allowing such blood to reachthe coronary arteries which might resuscitate the heart. Third, incardiac procedures, such isolation creates a working space into whichthe flow of blood and other fluids can be controlled or prevented so asto create an optimum surgical environment.

Using current techniques, isolation of the heart and coronary bloodvessels is accomplished by placing a mechanical cross-clamp externallyon the ascending aorta downstream of the ostia of the coronary arteries,but upstream of the brachiocephalic artery, so as to allow oxygenatedblood from the cardiopulmonary bypass system to reach the arms, neck,head, and remainder of the body. A catheter is then inserted directlyinto the ascending aorta between the cross-clamp and the aortic valve,and cardioplegic fluid is infused through the catheter into theascending aorta and coronary arteries to perfuse the myocardium. Anadditional catheter may be introduced into the coronary sinus forretrograde perfusion of the myocardium with cardioplegic fluid. Inaddition, the myocardium is usually cooled by irrigating with coldsaline solution and/or application of ice or cold packs to themyocardial tissue. Cardiac contractions will then cease.

Known techniques for performing major surgeries such as coronary arterybypass grafting and heart valve repair and replacement have generallyrequired open access to the thoracic cavity through a large open wound,known as a thoracotomy. Typically, the sternum is cut longitudinally (amedian sternotomy), providing access between opposing halves of theanterior portion of the rib cage to the heart and other thoracic vesselsand organs. An alternate method of entering the chest is via a lateralthoracotomy, in which an incision, typically 10 cm to 20 cm in length,is made between two ribs. A portion of one or more ribs may bepermanently removed to optimize access.

In procedures requiring a median sternotomy or other type ofthoracotomy, the ascending aorta is readily accessible for placement ofan external cross-clamp through this large opening in the chest.However, such surgery often entails weeks of hospitalization and monthsof recuperation time, in addition to the pain and trauma suffered by thepatient. Moreover, while the average mortality rate associated with thistype of procedure is about two to fifteen per cent for first-timesurgery, mortality and morbidity are significantly increased forreoperation. Further, significant complications may result from suchprocedures. For example, application of an external cross-clamp to acalcified or atheromatous aorta may cause the of release of emboli intothe brachiocephalic, carotid or subclavian arteries with seriousconsequences such as strokes. In up to 6% of the open-chest coronarybypass surgeries performed in the United States, there is noticeablemental deterioration which is commonly attributed to cerebral arterialblockage from emboli released during the bypass procedure. Methods anddevices are therefore needed for isolating the heart and coronaryarteries from the remainder of the arterial system, arresting cardiacfunction and establishing cardiopulmonary bypass without the open-chestaccess provided by a median sternotomy or other type of thoracotomy.Further, the methods and devices should facilitate such isolation of theheart and coronary arteries without the high risk of embolus productionassociated with external aortic cross-clamps.

Of particular interest to the present invention is the treatment ofheart valve disease. There are two major categories of heart valvedisease, namely, stenosis, which is an obstruction to forward blood flowcaused by a heart valve, and regurgitation, which is the retrogradeleakage of blood through a heart valve.

When it is necessary to repair or replace a malfunctioning heart valvewithin a patient, heretofore the repair or replacement has beenaccomplished by a major open-heart surgical procedure, requiring generalanesthesia and full cardiopulmonary by-pass with complete cessation ofcardiopulmonary activity. While the use of extracorporealcardiopulmonary by-pass for cardiac support has become well established,this use has involved median sternotomy or less commonly thoracotomywith all of the trauma that necessarily accompanies such a majorsurgical procedure. Such surgery usually includes one to two weeks ofhospitalization and months of recuperation time for the patient. Theaverage mortality rate with this type of procedure is about five to sixpercent, and the complication rate is substantially higher. Descriptionsof open-heart procedures for replacing heart valves can be found inGibbon's Surgery of the Chest, 5th Ed., David C. Sabiston, Jr., M.D.,Frank D. Spencer, M.D., 1990, Vol. II, Ch. 52, pp. 1566-1596, andTextbook of Interventional Cardiology, Eric J. Topol, 1990, Chs. 43-44,pp 831-867.

Endovascular surgical procedures on the heart have been developedrecently which, in contrast to open-heart surgical procedures, may havea reduced mortality rate, may require only local anesthesia, and maynecessitate only a few days of hospitalization. However, the range ofapplications of endovascular heart procedures other than those of thecoronary arteries, such as angioplasty and atherectomy, has beenlimited.

Some progress has been made in developing endovascular proceduresinvolving the heart valves. For example, for patients with severestenotic valve disease, who are too compromised to tolerate open-heartsurgery to replace the heart valve as described above, surgeons haveattempted endovascular balloon aortic or mitral valvuloplasty. Theseprocedures involve endovascularly advancing a balloon dilatationcatheter into the patient's vasculature until the balloon of thecatheter is positioned between the valve leaflets and then inflating theballoon to split the commissures in a diseased valve with commissuralfusion and to crack calcific plaques in a calcified stenotic valve.However, this method may provide only partial and temporary relief for apatient with a stenotic valve. The rapid restenosis and high mortalityfollowing balloon aortic valvuloplasty has led to virtual abandonment ofthis procedure as a treatment of the diseased aortic valve.

An endovascular treatment regimen for regurgitant heart valves, whichinvolves valve supplantation, has been disclosed in the patentliterature, but apparently the procedure has not been clinicallypracticed. In this procedure, it is conceived that an elongated catheteris used to insert a mechanical valve into the lumen of the aorta viaentry through a distal artery, for example, the brachial or femoralartery. One such mechanical valve is described in U.S. Pat. No.4,056,854 (Boretos et al.) that is designed to be positioned against theartery wall during forward flow, as compared to the mid-center positionof the valve described in U.S. Pat. No. 3,671,979 (Moulopoulos). Thevalve positioned against the arterial wall is intended to reduce thestagnation of blood flow and consequent thrombus and emboli formationcompared to a valve at mid-center position. The mechanical valvespreviously described require an elongated mounting catheter extendingout of the arterial entry point to maintain the position of the valve inthe descending aorta. These valves would be expected to present severalproblems. The valves do not provide a permanent or internalized system.Furthermore, since both involve a mechanical valve, which predisposesthe patient to thrombus formation and emboli, long term anticoagulanttherapy is required. A serious complication of long term anticoagulanttherapy is intracranial hemorrhage. Finally, the supplemental valve isplaced downstream from both the normal valve position and the coronaryostia, so normal heart and coronary artery hemodynamics are notrestored.

Of additional interest to the invention are techniques for establishingcardiopulmonary bypass and for performing interventional procedures inthe heart and great vessels which minimize trauma and risk ofcomplications resulting from vascular penetrations, whether percutaneouspunctures or surgical cut-downs. To establish cardiopulmonary bypassaccording to conventional techniques, a venous cannula is introducedinto a major vein such as the inferior vena cava, or into the heartitself, to withdraw deoxygenated blood from the patient and deliver thedeoxygenated blood to a CPB system for oxygenation. An arterial cannulais introduced into a major artery such as the aorta, an iliac artery, ora femoral artery, for delivering oxygenated blood from the CPB system tothe patient's arterial system.

For endovascular procedures such as angioplasty, atherectomy,valvuloplasty, cardiac mapping and ablation, and the like,interventional devices are introduced into a peripheral artery andtransluminally positioned at the treatment site where the procedure isperformed. For example, in angioplasty or atherectomy, a catheter isintroduced into a femoral artery and advanced through the aorta into acoronary artery to treat an occluded region therein. In somecircumstances, the use of CPB may be desirable during such procedures.If CPB is utilized during these procedures, the arterial and venous CPBcannulae are usually introduced into a femoral artery and femoral vein,respectively, by means of a surgical cut-down in the groin area on oneside of a patient's body. The endovascular interventional devices maythen be introduced into a femoral artery in the groin area on the otherside of the patient's body.

In order to minimize trauma and the risk of complications such asinfection, it is generally desirable to minimize the number of vascularpenetrations or “sticks” which are made in a patient during a procedure.Such penetrations are a significant cause of morbidity and mortality incardiac procedures. The risks are greater where the penetrations areeither surgical cut-downs or large percutaneous penetrations, as areusually required for introduction of venous and arterial CPB cannulaeand for some types of endovascular interventional devices. The risks areparticularly high when such penetrations are made on arterial vessels.

Moreover, in some cases, one or more of a patient's femoral arteries,femoral veins, or other vessels for arterial and venous access may notbe available for introduction of cannulae, due to inadequate vesseldiameter, vessel stenosis, vascular injury, or other conditions. In suchcases, there may not be sufficient arterial and venous access to permitthe use of femoral arterial and venous CPB cannulae as well as otherinterventional devices, such as an angioplasty catheter, atherectomycatheter or other device, introduced through a femoral vein or arterycontemporaneously as part of a single surgical procedure. Therefore,unless alternate arterial or venous access for one or more of thesecatheters can be found, the procedure cannot be performed usingendovascular techniques.

What have been needed and heretofore unavailable are methods and systemsfor satisfactorily performing various cardiovascular procedures,particularly procedures for heart valve placement or removal andreplacement, which do not require a thoracotomy. Improved methods anddevices are also needed for establishing CPB and performinginterventional procedures that reduce the number of arterial and venouspenetrations required for CPB cannulae and other endovascular devices.The methods and devices will preferably facilitate isolating the heartand coronary arteries from the remainder of the arterial system,arresting cardiac function, and establishing cardiopulmonary bypasswithout the open-chest access provided by a thoracotomy. The methods anddevices should minimize the number of arterial and venous penetrationsrequired in such closed-chest procedures, and desirably, should requireno more than one femoral arterial penetration and one femoral venouspenetration. In addition to procedures requiring arrest of cardiacfunction, the methods and devices should be useful for a variety ofclosed-chest interventional procedures that require the use ofcardiopulmonary bypass, even where cardiac function is not arrested. Thepresent invention satisfies these and other needs.

The descriptive terms downstream and upstream, when used herein inrelation to the patient's vasculature, refer to the direction of bloodflow and the direction opposite that of blood flow, respectively. In thearterial system, downstream refers to the direction further from theheart, while upstream refers to the direction closer to the heart. Theterms proximal and distal, when used herein in relation to instrumentsused in the procedure, refer to directions closer to and farther awayfrom the operator performing the procedure.

SUMMARY OF THE INVENTION

The present invention is directed to a method and system for anendovascular approach for preparing a patient's heart for cardiacprocedures which does not require a grossly invasive thoracotomy. Theinvention contemplates, at least in its preferred embodiments, thepossibility of effective ascending aortic occlusion, cardioplegia,venting, right heart deflation and topical cooling in association withextracorporeal cardiopulmonary by-pass all without necessitating amedian sternotomy or other thoracic incision.

The endovascular system of the invention includes an elongated catheterhaving proximal and distal ends and an occluding member on a distalportion of the catheter adapted to occlude a patient's ascending aorta.The catheter preferably has an inner lumen extending within the catheterto a port in the distal end of the catheter. The catheter is adapted tobe inserted into the patient's arterial system (e.g. through the femoralor brachial arteries) and to be advanced to the ascending aorta wherethe occluding member is expanded to occlude the aorta at that location.In so doing the left ventricle of the heart and an upstream portion ofthe ascending aorta are separated from the rest of the patient'sarterial system. This catheter thus constitutes an endovascularlyinserted, internal vascular clamp, similar in function to the external“cross-clamp” used in open cardiac surgical procedures. The internalclamp is less traumatic to the clamped vessel, and provides a lumen orworking channel through which instruments or fluids may be passed intoor withdrawn from the area upstream of the distal end of the clamp. Theoccluding member on the elongated catheter should be dimensioned so thatupon expansion it will be located downstream from the ostia for thecoronary arteries and upstream from the brachiocephalic artery so as toavoid blocking these arteries. In one presently preferred embodiment,the inner lumen of the occluding catheter is dimensioned to allow forthe passage therethrough of instruments for performing the cardiacprocedure.

Also included with the system is a cardiopulmonary by-pass system whichwithdraws blood from the patient's venous system, e.g. the femoral orjugular vein, removes CO₂ from and adds oxygen to the withdrawn blood,and then returns the oxygenated blood to the patient's arterial system,e.g. the femoral or brachial artery. The system is also provided withmeans to deliver a fluid containing cardioplegic material (e.g. anaqueous solution of KCl and/or magnesium procaine and the like) throughthe coronary arteries so as to paralyze the myocardium.

In a further aspect the present invention consists in a method forinducing cardioplegic arrest of a heart in situ in a patient's body,comprising the steps of:

-   (a) maintaining systemic circulation with peripheral cardiopulmonary    by-pass;-   (b) partitioning the coronary arteries from the ascending aorta by,    e.g., occluding the ascending aorta through a percutaneously placed    arterial balloon catheter;-   (c) introducing a cardioplegic agent into the coronary circulation;    and-   (d) venting the heart.

The method according to the present invention may be carried out onhumans or other mammalian animals. The method is of particularapplicability in humans as it allows an alternative approach to openheart surgery and the development of closed cardioscopic surgery. Themethod according to the invention enables a percutaneous by-pass systemto be associated with cardioplegia, venting and cooling of the heartwhich subverts the need for median sternotomy. This may, in turn, reducethe complications of the surgery.

In another aspect the present invention consists in a catheter for usein occluding the ascending aorta comprising an elongate tube having oneor more continuous lumina along its length, an inflatable cuff isdisposed about the tube adjacent one end thereof, the cuff being of sucha size that upon being inflated it is able to occlude the ascendingaorta of a patient.

The maintenance of the systemic circulation involves establishing acardiopulmonary by-pass. The blood may be drawn into the by-pass merelyby positioning a percutaneous catheter into the right atrium and/or intoone or both of the vena cavae through which venous blood may be drawnfrom the heart into an extracorporeal pump oxygenator. In more preferredembodiments of the invention a single catheter with two inflatablecuffs, or two separate catheters, each with an inflatable cuff areintroduced into the vena cavae to occlude them adjacent to their rightatrial inlets. This allows isolation of the right atrium and allowsblood to be drawn from the vena cavae into the by-pass system. There isalso preferably provision for percutaneous communication via onecatheter with the right atrium to allow infusion of saline into theright atrium. This infusion has the advantage that it allows the heartto be cooled and improves visual acuity within the right heart allowingdirect cardioscopic examination and/or intervention.

The catheter used to decompress the right atrium and to draw blood intothe by-pass is preferably introduced through the femoral vein bypercutaneous puncture or direct cut down. If other than simple venousdrainage is required catheters with inflatable cuffs, as describedabove, are placed preferably such that an inflatable cuff of the cannulais positioned within each of the inferior (suprahepatic) and superiorvena cavae. There is preferably a lumen in the cannula acting as acommon blood outlet from the vena cavae leading to the pump oxygenator.A separate lumen is preferably used to infuse saline between the twoinflated cuffs into the right atrium. If, alternatively, separatecatheters are used to occlude each of the inferior and superior venacavae then the cannula for the inferior vena cavae is preferablyintroduced percutaneously from the femoral vein and that for thesuperior vena cavae is introduced percutaneously through the jugular orsubclavian vein.

The ascending aorta is preferably occluded by a balloon catheterintroduced percutaneously or by direct cut-down through the femoralartery. This catheter must carry adjacent its tip an inflatable cuff orballoon of sufficient size that upon being inflated it is able tocompletely occlude the ascending aorta. The length of the balloon shouldpreferably not be so long as to impede the flow of blood or othersolution to the coronary arteries or to the brachiocephalic, leftcarotid or left subclavian arteries. A balloon length of about 40 mm anddiameter of about 35 mm is suitable in humans. The balloon may be of acylindrical, spherical or other appropriate shape to fully and evenlyaccommodate the lumen of the ascending aorta. This maximizes the surfacearea contact with the aorta, and allows for even distribution ofocclusive pressure.

The balloon of the catheter is preferably inflated with a salinesolution to avoid the possibility of introducing into the patient an airembolism in the event that the balloon ruptured. The balloon should beinflated to a pressure sufficient to prevent regurgitation of blood intothe aortic root and to prevent migration of the balloon into the rootwhilst not being so high as to cause damage or dilation to the aorticwall. An intermediate pressure of the order of 350 mmHg, for example,has been proven effective.

The aortic catheter is preferably introduced under fluoroscopic guidanceover a suitable guidewire. Transoesophageal echocardiography canalternatively be used for positioning the aortic catheter. The cathetermay serve a number of separate functions and the number of lumina in thecatheter will depend upon how many of those functions the catheter is toserve. The catheter can be used to introduce the cardioplegic agent,normally in solution, into the aortic root via one lumen. The luminaldiameter will preferably be such that a flow of the order of 250-500ml/min of cardioplegic solution can be introduced into the aortic rootunder positive pressure to perfuse adequately the heart by way of thecoronary arteries. The same lumen can, by applying negative pressure tothe lumen from an outside source, effectively vent the left heart ofblood or other solutions. It may also be desirable to introduce medicalinstruments and/or a cardioscope into the heart through another lumen inthe catheter. The lumen should be of a diameter suitable to pass afibre-optic light camera of no greater than 3 mm diameter. It ishowever, preferable that the diameter and cross-sectional design of theinternal lumina are such that the external diameter of the catheter inits entirety is small enough to allow its introduction into the adultfemoral artery by either percutaneous puncture or direct cut-down.

The oxygenated blood returning to the body from the by-pass system maybe conveyed into the aorta from another lumen in the cannula carryingthe balloon. In this case the returning blood is preferably discardedfrom the catheter in the external iliac artery. In another embodiment ofthe invention, and in order to reduce the diameter of the cathetercarrying the balloon, a separate arterial catheter of known type may beused to return blood to the patient from the by-pass system. In thiscase a short catheter is positioned in the other femoral artery toprovide systemic arterial blood from the by-pass system. The control endof the catheter, i.e. that end that remains outside of the body, shouldhave separate ports of attachment for the lumina. The catheter lengthshould be approximately 900 mm for use in humans.

The cardioplegic agent may be any of the known materials previouslyknown to be useful, or in the future found to be useful, as cardioplegicagents. The agent is preferably infused as a solution into the aorticroot through one of the lumina of the aortic catheter.

It is also preferred to depressurize the left atrium by venting thepulmonary artery via a catheter placed percutaneously from a peripheralvein into the pulmonary artery. This catheter may actually occlude thepulmonary artery to further prevent blood from flowing to the lungs.

With the heart paralyzed, the expandable member of the aortic catheterexpanded within the ascending aorta, and the cardiopulmonary bypassoperating, the heart is prepared for a cardiac procedure. While aparticularly attractive feature of the invention is that it prepares theheart for endovascular, thoracoscopic, and other minimally-invasiveprocedures, the invention can also be used to prepare the heart forconventional open-heart surgery via a thoracotomy. It should also benoted that, if during an endovascular cardiac procedure in accordancewith the invention it becomes necessary to perform an open-heartprocedure, the patient is already fully prepared for the open-heartprocedure. All that is necessary is to perform a median sternotomy toexpose the patient's heart for the conventional surgical procedure.

In a further aspect, the invention provides endovascular devices andmethods for partitioning a patient's ascending aorta between thecoronary ostia and the brachiocephalic artery to isolate the heart andcoronary arteries from the remainder of the arterial system, arrestcardiac function, and establish cardiopulmonary bypass. The inventionalso provides a system and method for arresting the heart thatfacilitate isolating the heart and coronary arteries from the remainderof the arterial system, arresting cardiac function, and establishingcardiopulmonary bypass without the need for a thoracotomy or an externalaortic cross-clamp.

Using the device, system and method of the invention, all blood flowthrough the ascending aorta may be blocked and cardioplegic fluid may beintroduced through the coronary arteries to perfuse the myocardium. Withthe patient connected to cardiopulmonary bypass equipment to maintaincirculation of oxygenated blood while the heart is stopped, surgicalprocedures may be performed on the heart, coronary blood vessels andother body structures using thoracoscopic and/or endovascular tools,without the need for a thoracotomy. Moreover, by partitioning the aortaby endovascular occlusion rather than by external cross-clamping, thedevice of the invention may substantially reduce the risk of embolusrelease associated with such cross-clamping.

In a particular aspect of the invention, an endovascular device forpartitioning the ascending aorta between the coronary ostia and thebrachiocephalic artery comprises a flexible shaft having a distal end, aproximal end, and a first inner lumen therebetween with an opening atthe distal end in communication with the first inner lumen. The shafthas a distal portion which is shaped so as to be positionable within theaortic arch such that the distal end is disposed in the ascending aortapointing toward the aortic valve. Preferably, the distal portion will beshaped so that the distal end of the shaft is spaced apart from anyinterior wall of the aorta, and particularly, so that the distal end isaligned with the center of the aortic valve. Expandable means aredisposed near the distal end of the shaft proximal to the opening at thedistal end for occluding the ascending aorta between the coronary ostiaand the brachiocephalic artery, thereby blocking substantially allsystolic and diastolic blood flow. The first inner lumen of the shaftmay be used to withdraw blood or other fluids from the ascending aorta,to introduce cardioplegic fluid into the coronary arteries forparalyzing the myocardium, and/or to introduce surgical instruments intothe ascending aorta, the coronary arteries, or the heart for performingcardiac procedures.

By “shaped,” it is meant that the distal portion of the shaft is presetin a permanent, usually curved or bent shape in an unstressed conditionto facilitate positioning the distal portion within at least a portionof the aortic arch, or that such a shape is imparted to the distalportion of the shaft by means of a shaping or deflecting elementpositioned over or within the shaft, as described in detail below.

In a preferred embodiment, the distal portion of the shaft is preshapedso as to have a generally U-shaped configuration in an unstressedcondition. Preferably, the U-shaped distal portion has a curvaturecorresponding to the curvature of the patient's aortic arch, usuallyhaving a radius of curvature in a range of 20 to 80 mm. In this way,when the preshaped distal portion is positioned in the aortic arch, thedistal end will be disposed in the ascending aorta spaced apart from theinterior wall thereof. Alternatively, the distal portion may havestraight or curved segments with bends of relatively small radiusbetween each segment to achieve a general “U” shape. The bends and/orsegments of the preshaped distal portion may be configured to engage theinterior wall of the aortic arch to deflect the distal end into adesired position in the ascending aorta. In another embodiment, thepreshaped distal portion may be “S”-shaped to facilitate positioningfrom a location superior to the aortic arch, such as through thebrachial or carotid arteries and the brachiocephalic artery.

The preshaped distal portion of the shaft may further have a distalsegment which is positioned in the ascending aorta and a proximalsegment which is positioned in the descending aorta, wherein the distalsegment is skewed (non-coplanar) relative to the proximal segment. Sucha configuration mirrors the orientation of the ascending aorta relativeto the aortic arch and descending aorta, facilitating more accurateplacement of the distal end in the ascending aorta, spaced apart fromthe interior wall thereof, and preferably, aligned with the center ofthe aortic valve.

The invention preferably includes means in the shaft for straighteningthe preshaped distal portion. Usually, the straightening means comprisesa straightening element slidably disposed in the first inner lumenhaving a stiffness greater than the stiffness of the preshaped distalportion. The straightening element may comprise a relatively stiffportion of a flexible guidewire extending through the first inner lumen,or a stylet having an axial passage through it for receiving a movableguidewire.

Preferably, the shaft has a bending stiffness selected to maintain theposition of the occluding means against systolic blood flow from thepatient's heart when the occluding means is expanded. Usually, the shafthas a bending modulus in a range of 70 to 100 kpsi.

In a further alternative embodiment, the distal portion of the shaft isshaped by a means for deflecting the distal portion of the shaft from agenerally linear configuration to one suitable for positioning in theaortic arch. In one embodiment, the deflecting means comprises a guidingcatheter having an interior lumen in which the shaft may be positioned,a preshaped or deflectable distal portion for positioning in the aorticarch, and a distal opening in communication with the interior lumenthrough which the distal end of the shaft may be advanced. In this way,the distal portion of the shaft is deflected by the guiding catheterinto a shape corresponding to the shape of the aortic arch, with thedistal end of the shaft and the occluding means disposed in theascending aorta. Similarly, in another embodiment, a shaping elementsuch as a preshaped stylet or guidewire may be positioned in an innerlumen of the shaft so as to deflect the distal portion of the shaft intoa shape generally conforming to the aortic arch.

Alternatively, the partitioning device may have at least one pull wireor push rod attached to the distal end of the shaft and extendingthrough an inner lumen to the proximal end. The distal portion may thusbe deflected to conform to the shape of the aortic arch by applyingtension to the pull wire or applying compression to the push rod.

In an exemplary embodiment, the occluding means has a collapsed profilefor insertion into an artery such as a femoral and an expanded profilefor occluding the ascending aorta, with the expanded profile diameterbeing about 2 to 10 times, and preferably 5 to 10 times, the collapsedprofile diameter. In a preferred embodiment, the occluding meanscomprises an inflatable balloon, preferably of a polyurethane orpolyurethane/polyvinyl blend. In one embodiment, the balloon has ablow-up ratio (defined as the ratio of the inflated outside diameter tothe deflated outside diameter before collapsing) in a range of200%-400%, and includes at least one pleat or fold when deflated whichallows the balloon to collapse to an even smaller collapsed profile.Through the use of such pleats or folds, a moderately compliant materialmay be used to maintain balloon shape and position under the conditionspresent in the ascending aorta, while accommodating a range of aorticdiameters. The balloon is further configured to maximize contact withthe aortic wall to resist displacement and prevent leakage around theballoon, preferably having a working surface for contacting the aorticwall with a length in the range of about 3 to about 7 cm when theballoon is expanded to fully occlude the vessel.

Where a balloon is used for the occluding means, the endovascular devicehas an inflation lumen extending through the shaft from the proximal endto the interior of the balloon, and means connected to the proximal endof the inflation lumen for delivering an inflation fluid to the interiorof the balloon. In one embodiment, the inflation fluid is a liquid suchas a saline solution with a radiographic contrast agent. In a particularpreferred embodiment, the inflation fluid delivery means and theinflation lumen are configured to inflate the balloon in less than about0.5 seconds. Usually, in this embodiment, the inflation fluid is a gassuch as carbon dioxide or helium. In this way, the balloon may be fullyinflated between systolic contractions of the heart, reducing thelikelihood of balloon displacement caused by high pressure blood flowduring systole.

The shaft of the endovascular device of the invention may have a varietyof configurations. The first inner lumen and inflation lumen may becoaxial, or a multi-lumen design may be employed. The shaft may furtherinclude a third lumen extending from the proximal end to the distal endof the shaft, allowing pressure distal to the occluding means to bemeasured through the third lumen. The shaft may also include means formaintaining the transverse dimensions of the first inner lumen, whichmay comprise a wire coil or braid embedded in at least the distalportion of the shaft to develop radial rigidity without loss oflongitudinal flexibility. The shaft preferably has a soft tip at itsdistal end to prevent damage to the heart valve if the catheter comesinto contact with the delicate valve leaflets.

The shaft preferably has a length of at least about 80 cm, usually about90-100 cm, to allow transluminal positioning of the shaft from thefemoral and iliac arteries to the ascending aorta. Alternatively, theshaft may have a shorter length, e.g. 20-60 cm, for introduction throughthe iliac artery, through the brachial artery, through the carotidartery, or through a penetration in the aorta itself.

In a particular embodiment, the first inner lumen in the shaft isconfigured to allow introduction of surgical or visualizationinstruments through the lumen for performing cardiac procedures upstreamof the occluding means. In this embodiment, the first inner lumenpreferably has a diameter of at least about 5 mm.

The endovascular device of the invention is particularly advantageous inthat it is readily positionable in the ascending aorta, resistsdisplacement caused by systolic blood flow, and maintains its positionspaced apart from the aortic wall and axially aligned with the center ofthe aortic valve. The endovascular device is long enough and flexibleenough to traverse the path through the femoral artery, iliac artery,descending aorta and aortic arch. At the same time, the device hassufficient pushability to be endovascularly introduced through thefemoral and iliac arteries and advanced to the ascending aorta bypushing on the proximal end. Moreover, the device has sufficient axial,bending, and torsional stiffness to allow the physician to control theposition of the occluding member from the proximal end, even when thedevice is in a tortuous vascular structure.

Because of its proximity to the left ventricle, the occluding means ofthe device is subject to significant forces from the outflow of bloodduring systole. Such forces could threaten to displace the occludingmeans either downstream where it might occlude the ostium of thebrachiocephalic or other artery, or upstream (in a recoil effect) wherethe occluding means might damage the aortic valve or occlude thecoronary ostia. Advantageously, the endovascular device of the inventionis configured to maintain the position of the occluding means in theascending aorta against the force of systolic outflow as the occludingmeans is expanded and retracted, as well as during the period in whichthe occluding means fully occludes the aorta but the heart remainsbeating.

In addition, the shaped distal portion of the device maintains thedistal end in a radial position spaced apart from the interior wall ofthe ascending aorta such that the distal opening is unobstructed andgenerally aligned with the center of the aortic valve. This facilitatesaspiration of blood, other fluids, or debris, infusion of fluids, orintroduction of instruments through the distal opening in theendovascular device without interference with the aortic wall or aorticvalve tissue.

In a further preferred embodiment, the invention provides a system forselectively arresting the heart which includes an endovascular aorticpartitioning device as just described, along with means for paralyzingthe patient's myocardium. Usually, the means for paralyzing themyocardium comprises means connected to the proximal end of the shaftfor delivering cardioplegic fluid through the first inner lumen and outof the opening at the distal end of the device upstream of the occludingmeans. In this way, the occluding means may be expanded to stop bloodflow through the ascending aorta, and cardioplegic fluid may bedelivered through the first inner lumen to the aortic root and thecoronary arteries to perfuse myocardial tissue, thereby arresting theheart. The system may further include a cardiopulmonary bypass systemhaving means for withdrawing blood from a venous location upstream ofthe heart, means for oxygenating the withdrawn blood, and means fordirecting the oxygenated blood to an arterial location downstream of theoccluding means.

According to the method of the invention, the distal end of the shaft ofthe endovascular partitioning device is introduced into a blood vesseldownstream of the patient's aortic arch. The shaft is transluminallypositioned so that the distal end is in the ascending aorta and theexpandable occluding member attached to the shaft near the distal end isdisposed between the coronary ostia and brachiocephalic artery. Theoccluding member is then expanded within the ascending aorta tocompletely block blood flow therethrough for a plurality of cardiaccycles.

In those embodiments in which the shaft of the partitioning device has apreshaped, usually U-shaped distal portion, the method will usuallyinclude the step of straightening the preshaped distal portion tofacilitate introduction into the blood vessel, usually by positioning astylet or guidewire in an inner lumen in the shaft. The stylet may bewithdrawn from the shaft as the distal portion is advanced into theascending aorta to allow the distal portion to resume its preshapedconfiguration. In a particular embodiment, the method may furtherinclude, before the step of introducing the shaft into the blood vessel,the steps of determining a size of the patient's aortic arch, andselecting a shaft having a U-shaped distal portion with a sizecorresponding to the size of the aortic arch.

Preferably, the shaft of the partitioning device is introduced through afemoral or iliac artery, brachial artery, carotid artery or other arterywhich is percutaneously accessible without a thoracotomy. In this way,the device may be introduced and advanced into position with thepatient's sternum and rib cage intact.

When the occluding member is an inflatable balloon, the method furtherincludes the step of delivering an inflation fluid to the balloonthrough an inner lumen in the shaft of the device. The inflation fluidmay be either a liquid or a gas, and, in one embodiment, is delivered ata rate to completely occlude the aorta between systolic contractions ofthe heart, usually in less than about 0.5 second.

The method may further include paralyzing the patient's myocardium whilethe occluding means is expanded in the ascending aorta. Usually, thiswill be accomplished by infusing cardioplegic fluid through an innerlumen in the shaft of the partitioning device into the ascending aortaupstream of the occluding member. The cardioplegic fluid perfuses themyocardium through the coronary arteries to arrest heart contractions.In this embodiment, the method further includes the steps of withdrawingblood from a venous location upstream of the patient's heart,oxygenating the withdrawn blood, and directing the oxygenated blood toan arterial location downstream of the occluding member, therebymaintaining circulation of oxygenated blood throughout the remainder ofthe patient's arterial system.

With the partitioning device in position, the heart and coronaryarteries isolated from the remainder of the arterial system, and theheart stopped, various diagnostic and interventional procedures may beperformed. For example, instruments may be introduced for repairing orreplacing the aortic or mitral valve. In this embodiment, the methodwill include the step of aligning the distal end of the shaft with thecenter of the aortic valve to facilitate introduction of instrumentsthrough the inner lumen of the shaft into the ascending aorta andbetween the valve leaflets into the left ventricle of the heart.

Thus, using the system and method of the invention, a patient's heartcan be arrested and the patient placed on cardiopulmonary bypass withouta thoracotomy, thereby reducing mortality and morbidity, decreasingpatient suffering, reducing hospitalization and recovery time, andlowering medical costs relative to previous open-chest procedures. Theendovascular partitioning device of the invention permits blood flowthrough the ascending aorta to be completely blocked between thecoronary ostia and the brachiocephalic artery in order to isolate theheart and coronary arteries from the remainder of the arterial system.This has significant advantages over the aortic cross-clamps used incurrent cardiac procedures, not only obviating the need for athoracotomy, but providing the ability to stop blood flow through theaorta even when calcification or other complications would make the useof an external cross-clamp undesirable.

With the endovascular partitioning device in place, the heart arrestedand cardiopulmonary bypass established, the patient is prepared for avariety of surgical and diagnostic procedures, including repair orreplacement of aortic, mitral and other heart valves, repair of septaldefects, pulmonary thrombectomy, coronary artery bypass grafting,angioplasty, atherectomy, electrophysiological mapping and ablation,treatment of aneurysms, myocardial drilling, as well as neurovascularand neurosurgical procedures. While such procedures may be performedthrough a thoracotomy in the conventional manner, the invention providesthe capability for performing procedures such as heart valve replacementor coronary artery bypass grafting using minimally-invasive techniques,either by means of surgical tools introduced endovascularly through thepartitioning device itself, or by means of thoracoscopic toolsintroduced through small incisions in the chest wall.

In a presently preferred embodiment of the invention directed toendovascular cardiac procedures, the occlusion catheter is adapted todeliver instruments to be used during the procedures such as the removalof an in-place aortic valve, the insertion and placement of a new valve,and the securing of the new valve at the desired location. In theseprocedures, the expanded expandable member on the distal end of theocclusion catheter firmly secures the distal end of the catheter withinthe aorta to allow for the accurate guidance of instruments to be usedduring the procedure.

By partitioning the arterial system with the elongated aortic catheterin this manner, a body of clear fluid can be maintained in the aorticregion upstream from the expanded distal end of the aortic catheter tofacilitate the imaging, e.g. angioscopic observation, of the cardiacprocedure. A continual flow of clear fluid may be directed to thesurgical field in order to maintain fluid clarity sufficient for imagingthe site during the procedure. The pressure of the body of irrigationfluid at the surgical site can be maintained at a level equal to orhigher than the fluid pressure in the patient's left atrium to preventthe intrusion of blood from the left atrium into the left ventricle,which can interfere with the imaging. The temperature of the irrigatingfluid should be about 4° C. in order to reduce myocardial oxygen demand.

In order to deliver cardioplegic fluids to the myocardium, in some casesit is preferred to carry out retrograde perfusion of the coronarycirculation. Using this technique, a physician will percutaneouslyintroduce a catheter through a major vein, e.g. the right internaljugular vein, and advance the catheter in the venous system until thedistal end of the catheter extends into the coronary sinus through thedischarge opening thereof in the right atrium. Preferably, the catheterhas an inflatable balloon on the distal end thereof, such as those shownin U.S. Pat. No. 4,689,041, U.S. Pat. No. 4,943,277, and U.S. Pat. No.5,021,045, which are incorporated herein by reference. When inflated,the balloon blocks the discharge opening of the coronary sinus topreclude loss of cardioplegic fluid therefrom. With the dischargeopening of the coronary sinus blocked off, aqueous liquid or other fluidcontaining cardioplegic material is delivered through the catheter intothe coronary sinus at sufficient pressure so that it passes into themyocardium via the capillary bed between the venous and arterial systemstherein so as to paralyze the entire myocardium. Typically, cardioplegicsolution pressure within the coronary sinus should be less than 50 mm Hgto avoid tissue damage. After passing through the myocardium, thecardioplegic liquid will pass through the coronary arteries in aretrograde fashion to be discharged through the coronary ostia into theupstream portion of the ascending aorta. The cardioplegic fluid whichdischarges from the coronary ostia will initially be very opaque due toblood being flushed out of the coronary circulation, but eventually thefluid will become clear and may be conveniently used to form andmaintain the body of clear fluid at the surgical site to facilitate theimaging thereof during the procedure. In some instances, cardioplegicliquid may instead be delivered through the coronary arteries in anantegrade fashion, either via catheters placed through the coronaryostia into the coronary arteries or by delivery via the aortic catheterdirectly into the aortic root.

The left atrium is preferably decompressed by one of two methods. Thefirst involves a catheter passing into the pulmonary trunk. The catheterdescribed is advanced through the patient's venous system, e.g. throughthe right internal jugular vein, through the right atrium and rightventricle, and into the pulmonary trunk. This catheter can vent fluidfrom the pulmonary trunk via an inner lumen extending from its distalport to a port in its proximal end located outside the patient. It maybe advantageous to have an inflatable member located at the distal endof the venting catheter. The inflatable member is dimensioned so thatupon inflation it will block the pulmonary trunk while simultaneouslyventing the trunk through the inner lumen of the catheter, which extendsthrough the catheter from a port in its distal end to a port in itsproximal end located outside of the patient.

In an alternative method, as described in U.S. Pat. No. 4,889,137(Kolobow) which is incorporated herein by reference, a catheter isadvanced in essentially the same manner as that described above untilthe distal end is within the pulmonary trunk. As described in thispatent, springs or other means are provided on the exterior of thecatheter at the locations where the catheter will extend through thepulmonary and tricuspid valves in order to hold the valves at leastpartially open and thereby vent the pulmonary artery and decompress theleft atrium.

The present invention further provides endovascular devices and methodsfor establishing cardiopulmonary bypass and performing interventionalprocedures within the heart and great vessels with a minimum of arterialand venous penetrations. Using the devices and methods of the invention,all blood flow through the ascending aorta may be blocked, cardioplegicfluid may be introduced through the coronary arteries to perfuse themyocardium, and oxygenated blood from a CPB system may be infused intothe arterial system downstream from the point of aortic occlusion, allthrough a single femoral arterial penetration. Moreover, blood may bevented from the heart to prevent distension of the myocardium, anddeoxygenated blood withdrawn from a venous location for oxygenation bythe CPB system, all through a single femoral or jugular venouspenetration.

In an additional aspect of the invention, an endovascular interventionaldevice facilitating cardiopulmonary bypass comprises a bypass cannulahaving a distal end configured for introduction into a blood vessel, aproximal end, a blood flow lumen therebetween, and a port at the distalend in fluid communication with the blood flow lumen. Means are providedat the proximal end of the bypass cannula for fluidly connecting theblood flow lumen to a cardiopulmonary bypass (CPB) system. An elongatedcatheter shaft is coupled to the bypass cannula so as to extend distallyfrom the distal end thereof, and has a distal end configured forpositioning in the heart or in a great vessel near the heart, a proximalend, and an inner lumen therebetween. Interventional means are providedat the distal end of the catheter shaft for performing an interventionalprocedure in the heart or in a great vessel near the heart.

In a preferred embodiment, utilized in the patient's arterial system,the interventional means comprises a device for partitioning theascending aorta between the coronary ostia and the brachiocephalicartery. In this embodiment, an expandable means such as an inflatableballoon is disposed at the distal end of the catheter shaft foroccluding the ascending aorta between the coronary ostia and thebrachiocephalic artery so as to block substantially all blood flowtherethrough. Additionally, the device may include means at the proximalend of the catheter shaft for delivering cardioplegic fluid through theinner lumen of the catheter shaft into the patient's ascending aortaupstream of the occluding means. The bypass cannula is configured forintroduction into an artery in the patient, and the blood flow lumen inthe bypass cannula is connected to a means for delivering oxygenatedblood into the patient's arterial system, such as a cardiopulmonarybypass system.

In another embodiment, utilized in the patient's venous system, theinterventional means comprises at least one inflow port at or near thedistal end of the catheter shaft for withdrawing blood from within thepatient's heart or great vessel. The inflow port is in fluidcommunication with the inner lumen of the catheter shaft for receivingblood from the heart or great vessel. An inflatable balloon may also beprovided near the distal end of the catheter shaft. In this embodiment,the bypass cannula will be positioned in a vein in the patient, and theblood flow lumen in the bypass cannula will be connected to a means forreceiving deoxygenated blood from the patient's venous system, such as aCPB system.

In one embodiment, the catheter shaft is fixed to the bypass cannula,and may be an integral part thereof, i.e., an extension from the distalend of the bypass cannula. In this configuration, the bypass cannula hasa lumen, which may comprise the blood flow lumen, in fluid communicationwith the inner lumen in the catheter shaft. Alternatively, the cathetershaft is slidably disposed in the blood flow lumen of the bypasscannula, and may be removable from the bypass cannula, and/or limited inits movement relative to the bypass cannula. The bypass cannula mayfurther be provided with a plurality of ports along a distal portion ofits length in fluid communication with the blood flow lumen to enhancethe flow of blood into or out of the blood flow lumen. In the arterialembodiment, the blood flow lumen is preferably configured to facilitatea fluid flow of at least about 4 liters/minute at a pressure of lessthan about 250 mmHg.

The bypass cannula may further have an adaptor assembly mounted to itsproximal end. The adaptor assembly has first and second access ports incommunication with the blood flow lumen, the first access port beingconfigured to receive the catheter shaft, and the second access portbeing configured for connection to the oxygenated blood delivery means(in the arterial embodiment) or a means for receiving and oxygenatingdeoxygenated blood (in the venous embodiment). Usually, a hemostasisvalve or other sealing means is mounted in the first access port toprevent leakage of blood therefrom, both when the catheter shaft isinserted through the first access port as well as when the cathetershaft is removed from the first access port.

In a preferred embodiment, the catheter shaft has a length of at leastabout 80 cm to facilitate transluminal positioning from a femoral veinor artery into the heart or into a great vessel such as the ascendingaorta or inferior vena cava near the heart. The bypass cannula willusually have a somewhat shorter length. In the arterial embodiment, thebypass cannula has a length between about 10 cm and 60 cm, andpreferably about 15 cm to 30 cm, such that the outflow port at thedistal end of the bypass cannula is disposed a substantial distancedownstream of the occluding member on the catheter shaft. On the venousside, the bypass cannula is preferably about 50 cm to 90 cm in length soas to extend from a femoral vein to a point in the inferior vena cavanear the heart, to a point within the right atrium of the heart, or to apoint in the superior vena cava near the heart. Alternatively, thevenous bypass cannula may be configured for introduction into theinternal jugular vein and positioning therefrom into the superior venacava, the right atrium, or the inferior vena cava. The catheter shaft inthe venous embodiment preferably has a length of between 50 cm and 70 cmso as to reach from the distal end of the bypass cannula through theright atrium and right ventricle, and into the pulmonary artery towithdraw blood therefrom.

According to the method of the invention, a distal end of a bypasscannula is positioned in a blood vessel of a patient, and a proximal endof the bypass cannula is connected to a CPB system to permit blood flowthrough a blood flow lumen in the bypass cannula between the bloodvessel and the CPB system. An interventional device is then introducedthrough the blood flow lumen of the bypass cannula into the blood vesseland advanced into the heart or into a great vessel near the heart toperform an interventional procedure therein.

In a particular embodiment, the bypass cannula is introduced into anartery downstream of the patient's ascending aorta, and a distal end ofa catheter shaft is introduced into the artery through the blood flowlumen in the bypass cannula. The catheter shaft is transluminallypositioned so that an expandable occluding member attached to thecatheter shaft near the distal end is disposed between the patient'scoronary ostia and the patient's brachiocephalic artery. Oxygenatedblood is infused into the artery downstream of the occluding memberthrough a lumen in the bypass cannula. The occluding member is expandedwithin the ascending aorta to completely block blood flow therethroughfor a plurality of cardiac cycles. The patient's myocardium is thenparalyzed.

In most embodiments, the bypass cannula will be connected to a CPBsystem which withdraws blood from a venous location in the patient,oxygenates the blood, and delivers the oxygenated blood to the bloodflow lumen in the bypass cannula on the arterial side. The deoxygenatedblood may be withdrawn through a blood flow lumen in a venous cannulapositioned in a vein such as a femoral vein or internal jugular vein.Also, a cardiac venting catheter may be positioned in the heart, usuallyin the pulmonary artery, to withdraw blood therefrom and deliver it tothe CPB system. In an exemplary embodiment, the cardiac venting catheteris introduced through the blood flow lumen in the venous cannula.Preferably, the venous and arterial bypass cannulae are introduced intoa femoral vein and femoral artery, respectively, in the groin area onthe same side of the patient. In this way, both the venous and arterialbypass cannulae, as well as the devices introduced therethrough, may beintroduced through a single surgical cut-down or percutaneous punctureson a single side of the patient.

Thus, using the system and method of the invention, a patient's heartcan be arrested and the patient placed on cardiopulmonary bypass withouta conventional gross thoracotomy, thereby reducing mortality andmorbidity, decreasing patient suffering, reducing hospitalization andrecovery time, and lowering medical costs relative to previousopen-chest procedures. The endovascular partitioning device of theinvention permits blood flow through the ascending aorta to becompletely blocked between the coronary ostia and the brachiocephalicartery in order to isolate the heart and coronary arteries from theremainder of the arterial system. This has significant advantages overthe aortic cross-clamps used in current cardiac procedures, not onlyobviating the need for a gross thoracotomy, but providing the ability tostop blood flow through the aorta even when calcification or othercomplications would make the use of an external cross-clamp undesirable.Moreover, the device and method of the invention accomplish this with aminimum of arterial penetrations, thereby minimizing trauma and the riskof complications such as infection.

The system and method of the invention may further be useful to providecardiopulmonary bypass during endovascular interventional procedures inwhich cardiac function may or may not be arrested. Such procedures mayinclude angioplasty, atherectomy, heart valve repair and replacement,septal defect repair, treatment of aneurysms, myocardial mapping andablation, myocardial drilling, and a variety of other procedures whereinendovascular interventional devices are introduced through the bypasscannula of the invention and advanced into the heart or great vessels.In this way, the invention facilitates cardiopulmonary bypass duringsuch procedures without requiring additional arterial or venouspenetrations.

The occluding aortic catheter with an expandable occluding member on thedistal end, coupled with cardiopulmonary bypass, cardioplegia, anddecompression of the left atrium, provides for a unique endovascularapproach to a wide variety of cardiac procedures, an approach which doesnot require invasive thoracic or abdominal surgery. In addition thesystem may be used in minimally invasive cardiac procedures underthoracoscopic guidance, working through incisions in the patient's chestfrom outside the patient's body. In these instances the occludingcatheter need not have an inner lumen for delivery of fluids and thelike. The catheter and method according to the present invention can beused to induce cardioplegic arrest and may be used in a number ofsurgical procedures. These include the following:

(1) Coronary artery revascularization such as:

-   -   -   (a) angioscopic laser introduction or angioscopic balloon            angioplasty catheter introduction into the coronary arteries            via one lumen of the aortic catheter; or        -   (b) thoracoscopic dissection of one or both of the mammary            arteries with revascularization achieved by distal            anastomoses of the internal mammary arteries to coronary            arteries via a small left anterior thoracotomy, incision,            puncture, or trocar.

(2) Secundum-type atrial septal defect repair such as by:

-   -   -   (a) “Closed” thoracoscopic or cardioscopic closure, or        -   (b) Closure as an “open” procedure via a mini-right            thoracotomy.

(3) Sinus venosus defect repairs or partial anomalous pulmonary venousdrainage repairs similar to 2 above.

(4) Infundibular stenosis relief by thoracoscopic or cardioscopictechniques.

(5) Pulmonary valvular stenosis relief by thoracoscopic or cardioscopictechniques.

(6) Mitral or tricuspid valve surgery via a small right lateralthoracotomy, incision, puncture, or trocar.

(7) Aortic stenosis relief by the introduction of instrumentation via alumen in the aortic catheter into the aortic root.

(8) Left ventricular aneurysm repair via a small left anteriorthoracotomy.

Moreover, as mentioned, the system may even be employed in conventionalopen-heart procedures. These and other advantages of the invention willbecome more apparent from the following detailed description of theinvention when taken in conjunction with the accompanying exemplarydrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a cardiac access system embodyingfeatures of the invention.

FIG. 2 is an enlarged view, partially in section, of the occludingcatheter shown in FIG. 1 disposed within the ascending aorta.

FIG. 3 is a transverse cross-sectional view of the occluding cathetershown in FIG. 2 taken along the lines 3—3.

FIG. 4. is an enlarged view, partially in section, of the retrogradecardioplegia delivery catheter and the pulmonary venting catheter shownin FIG. 1.

FIG. 5 is an elevational view, partially in section of the occludingcatheter shown in FIG. 2 schematically illustrating the removal of anaortic heart valve.

FIG. 6 schematically illustrates the introduction of a prosthetic valveinto the region of the ascending aorta from which the original heartvalve had been removed.

FIG. 7 schematically illustrates securing a mounting skirt on theprosthetic valve to the wall of the ascending aorta.

FIG. 8 schematically illustrates securing the upper extensions of thevalve to the aortic wall.

FIG. 9 schematically illustrates an alternate means for removing a heartvalve.

FIG. 10 is an enlarged perspective view of the cutting member of thecatheter shown in FIG. 9.

FIG. 11 schematically illustrates another alternate means for removing aheart valve.

FIGS. 12 and 13 schematically illustrate an alternate embodiment of avalve introducing device and the method of discharging a prosthetic orreplacement valve.

FIG. 14 schematically represents in an elevational view a prostheticheart valve.

FIG. 15 is a top view of the prosthetic heart valve shown in FIG. 14.

FIG. 16 is a schematic partly cut-away representation of a patient'sheart having percutaneous catheters placed therein for carrying out themethod according to the present invention;

FIG. 17 is a similar view to FIG. 1 showing the aortic catheter inposition but including an angioscope and a left ventricular ventingcannula introduced into the aortic root and left ventricle respectively,via separate lumina within the aortic catheter;

FIG. 18 is a front elevational view of part of the vascular system of apatient showing, inter alia, the aortic balloon catheter positioned inthe ascending aorta via the femoral artery;

FIG. 19 is a side elevational view of the control end of the aorticcatheter according to the present invention;

FIG. 20 is a partly cut away side elevational view of the balloon end ofthe catheter of FIG. 19 in an inflated condition;

FIG. 21 a is a cross-sectional view of the catheter of FIG. 19intermediate the control end and the balloon end;

FIG. 21 b is an alternative cross-sectional arrangement of the lumina inthe catheter of FIG. 19;

FIG. 22 is a cross-sectional view through the balloon end of thecatheter of FIG. 19;

FIGS. 23 a and 23 b show schematically two alternative arrangements tothe catheter shown in FIG. 19;

FIGS. 24 a and 24 b show schematically two alternative catheterarrangements for the isolation of the right atrium and venous drainage.

FIG. 25 is a side elevational view of an endovascular device forpartitioning the ascending aorta between the coronary ostia andbrachiocephalic artery constructed in accordance with the principles ofthe present invention.

FIG. 25A is an end view of a distal portion of the device of FIG. 25illustrating the skew of the shaped distal portion.

FIGS. 25B and 25C are side elevational views showing alternativeembodiments of the shaped distal portion of the device of FIG. 25.

FIG. 26A is a perspective view of a distal portion of the device of FIG.25 in a first embodiment thereof.

FIG. 26B is a perspective view of a distal portion of the device of FIG.25 in a second embodiment thereof.

FIGS. 27 and 28 are transverse cross-sections taken along lines 27—27and 28—28 in FIGS. 26A and 26B, respectively.

FIGS. 29A and 29B are transverse cross-sections taken along line 29—29in FIG. 26A, showing alternative embodiments of the shaft of the deviceillustrated therein.

FIG. 30 is a transverse cross section taken along line 30—30 in FIG.26B.

FIG. 31 is a front view of a portion of a patient's arterial systemillustrating the introduction and advancement of the device of FIG. 25in the femoral artery, iliac artery and aorta.

FIG. 32 schematically illustrates a system for arresting the heartconstructed in accordance with the principles of the present invention,wherein the device of FIG. 25 is positioned in the ascending aorta withcardioplegic fluid delivery means connected to the proximal end and acardiopulmonary bypass system connected to the patient.

FIG. 33 illustrates the distal portion of the device of FIG. 25positioned in the ascending aorta with the occluding means expanded anda tissue cutting device extended from the distal end.

FIGS. 34A-34B are side and transverse cross-sections, respectively, ofan alternative embodiment of an endovascular partitioning deviceconstructed in accordance with the principles of the present invention.

FIGS. 35A-35B are side elevational and transverse cross-sectional views,respectively, of a further alternative embodiment of an endovascularpartitioning device constructed in accordance with the principles of thepresent invention.

FIG. 36A is a side elevational view of still another embodiment of anendovascular partitioning device constructed in accordance with theprinciples of the invention.

FIG. 36B is a transverse cross section taken along the line 36B—36B inFIG. 36A, showing a shaping element positioned in an inner lumen in theshaft.

FIG. 37A is a side elevational view of a further alternative embodimentof an endovascular partitioning device constructed in accordance withthe principles of the present invention.

FIG. 37B is a transverse cross-section taken through line 37B—37B inFIG. 37A.

FIG. 37C is a transverse cross-section taken through line 37C—37C inFIG. 37A, showing a hemostasis valve with the aortic occlusion catheterremoved from the blood flow lumen in the bypass cannula in the device ofFIG. 37A.

FIG. 37D is a perspective view of an obturator and guidewire for usewith the infusion tube in the device of FIG. 37A.

FIG. 37E is a side cross-sectional view of the partitioning device ofFIG. 37A.

FIG. 38A is a perspective view of a cardiac venting device constructedin accordance with the principles of the present invention

FIG. 38B is a transverse cross-section taken through line 38B—38B inFIG. 38A.

FIG. 38C is a transverse cross-section taken through line 38C—38C inFIG. 38A, showing the hemostasis valve with the venting catheter removedfrom blood flow lumen of the bypass cannula.

FIG. 38D is a perspective view of an alternative configuration of adistal portion of the device of FIG. 38A.

FIG. 38E is a perspective view of an obturator to facilitateintroduction of the device of FIG. 38A.

FIG. 38F is a side cross-sectional view of the cardiac venting device ofFIG. 38A.

FIG. 39A is side elevational view of a further embodiment of the cardiacventing device of the present invention.

FIG. 39B is a transverse cross-section taken through line 39B—39B inFIG. 39A.

FIG. 39C is a side elevational view of an alternative configuration of adistal portion of the device of FIG. 39A.

FIG. 39D is transverse cross-section taken through line 39D—39D in FIG.39C.

FIG. 40 is a front partial cut-away view of a patient's body showing thepositioning of the aortic partitioning device and cardiac venting devicein accordance with the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a cardiac access system including an endovasculardevice for partitioning the ascending aorta, as well as a system forselectively arresting the heart, which are useful in performing avariety of cardiovascular, pulmonary, neurosurgical, and otherprocedures. The procedures with which the invention will find useinclude repair or replacement of aortic, mitral, and other heart valves,repair of septal defects, pulmonary thrombectomy, electrophysiologicalmapping and ablation, coronary artery bypass grafting, angioplasty,atherectomy, treatment of aneurysms, myocardial drilling andrevascularization, as well as neurovascular and neurosurgicalprocedures. The invention is especially useful in conjunction withminimally-invasive cardiac procedures, in that it allows the heart to bearrested and the patient to be placed on cardiopulmonary bypass usingonly endovascular devices, obviating the need for a thoracotomy or otherlarge incision. Moreover, even in conventional open-chest procedures,the endovascular aortic partitioning device of the invention willfrequently find use where an external cross-clamp would raisesubstantial risks of embolus release due to calcification or otheraortic conditions.

Reference is made to FIG. 1 which schematically illustrates the overallcardiac accessing system of the invention and the individual componentsthereof. The accessing system includes an elongated aortic occlusion ordelivery catheter 10 which has an expandable member 11 on a distalportion of the catheter which, when inflated as shown, occludes theascending aorta 12 to separate the left ventricle 13 and upstreamportion of the ascending aorta from the rest of the patient's arterialsystem and securely positions the distal end of the catheter within theascending aorta. A cardiopulmonary by-pass system 18 removes venousblood from the femoral vein 16 through the blood withdrawal catheter 17as shown, removes CO₂ from the blood, oxygenates the blood, and thenreturns the oxygenated blood to the patient's femoral artery 15 throughthe return catheter 19 at sufficient pressure so as to flow throughoutthe patient's arterial system except for the portion blocked by theexpanded occluding member 11 on the aortic occluding catheter 10. Aretrograde cardioplegia balloon catheter 20 is disposed within thepatient's venous system with the distal end of the catheter extendinginto the coronary sinus 21 (shown in FIG. 4) to deliver a fluidcontaining cardioplegic agents to the myocardium in a retrograde mannerthrough the patient's coronary venous system to paralyze the entiremyocardium.

The elongated occluding catheter 10 extends through the descending aortato the left femoral artery 23 and out of the patient through a cut down24. The proximal extremity 25 of the catheter 10 which extends out ofthe patient is provided with a multi-arm adapter 26 with one arm 27adapted to receive an inflation device 28. The adapter 26 is alsoprovided with a second arm 30 with main access port 31 through whichpasses instruments, a valve prosthesis, an angioscope, irrigation fluidand the like. A third arm 32 connected to by-pass line 33 is provided todirect blood, irrigation fluid, and the like to or from the system. Asuitable valve 34 is provided to open and close the by-pass line 33 anddirect the fluid passing through the by-pass line to a discharge line 35or a line 36 to a blood filter and recovery unit 37. A return line maybe provided to return any filtered blood, which will be describedhereinafter, to the cardiopulmonary by-pass system 18 or other bloodconservation system.

The details of the aortic occlusion catheter 10 and the disposition ofthe distal extremity thereof within the aorta are best illustrated inFIGS. 2 and 3. As indicated, the catheter 10 includes an elongatedcatheter shaft 39 which has a first inner lumen 40 in fluidcommunication with the main access port 31 in the second arm of theadapter 26 and is adapted to facilitate the passage of instruments, avalve prosthesis, an angioscope, irrigation fluid, and the liketherethrough and out the distal port 41 in the distal end thereof. Asupporting coil 42 may be provided in the distal portion of the firstinner lumen 40 to prevent the catheter shaft 39 from kinking as it isadvanced through the aortic arch. The shaft 39 is also provided with asecond inner lumen 43 which is in fluid communication with the interiorof the occluding balloon 11.

A retrograde cardioplegia balloon catheter 20, which is shown in moredetail in FIG. 4, is introduced into the patient's venous system throughthe right internal jugular vein 44 and is advanced through the rightatrium 45 and into the coronary sinus 21 through the coronary sinusdischarge opening 46 in the right atrium. The retrograde catheter 20 isprovided with a balloon 47 on a distal portion of the catheter 20 whichis adapted to occlude the coronary sinus 21 when inflated. A liquidcontaining a cardioplegic agent, e.g. an aqueous KCl solution, isintroduced into the proximal end 48 of the catheter 20, which extendsoutside of the patient, under sufficient pressure so that the fluidcontaining the cardioplegic agent can be forced to pass through thecoronary sinus 21, through the capillary beds (not shown) in thepatient's myocardium, through the coronary arteries 50 and 51 and ostia52 and 53 associated with the respective coronary arteries into theblocked off portion of the ascending aorta 12 as shown.

A pulmonary venting catheter 54 is also shown in FIG. 4 disposed withinthe right internal jugular vein 44 and extending through the rightatrium 45 and right ventricle 55 into the pulmonary trunk 56. Thecatheter 54 passes through tricuspid valve 57 and pulmonary valve 58. Aninflatable occluding balloon 60 may be provided as shown on a distalportion of the pulmonary venting catheter 54 which is inflated toocclude the pulmonary trunk 56 as shown. The pulmonary venting catheter54 has a first inner lumen 61 which extends from the distal end of thecatheter to the proximal end of the catheter which vents fluid from thepulmonary trunk 56 to outside the patient's body either for discharge orfor passage to the blood recovery unit and thereby decompresses the leftatrium 14 through the pulmonary capillary beds (not shown). The catheter54 has a second inner lumen 62 which is adapted to direct inflationfluid to the interior of the inflatable balloon 60.

To set up the cardiac access system, the patient is initially placedunder light general anesthesia. The withdrawal catheter 17 and thereturn catheter 19 of the cardiopulmonary by-pass system 18 arepercutaneously introduced into the right femoral vein 16 and the rightfemoral artery 15, respectively. An incision 24 is also made in the leftgroin to expose the left femoral artery 23 and the aortic occludingcatheter 10 is inserted into the left femoral artery through an incisiontherein and advanced upstream until the balloon 11 on the distal end ofthe occluding catheter 10 is properly positioned in the ascending aorta12. Note that by-pass could similarly be established in the left groinand the aortic occlusion catheter put into the right femoral artery. Theretrograde perfusion catheter 20 is percutaneously inserted by asuitable means such as the Seldinger technique into the right internaljugular vein 44 or the subclavian vein and advanced into the rightatrium 45 and guided through the discharge opening 46 into the coronarysinus.

The pulmonary venting catheter 54 is advanced through the right internaljugular vein 44 or the subclavian vein (whichever is available afterintroduction of retrograde perfusion catheter 20) into the right atrium45, right ventricle 55, and into the pulmonary trunk 56. The occludingballoon 60 may be inflated if necessary by inflation with fluid passingthrough the lumen 62 to block the pulmonary trunk 56 and vent bloodtherein through the lumen 61 where it is discharged through the proximalend of the catheter which extends outside of the patient. The venting ofthe pulmonary trunk 56 results in the decompressing of the left atrium14. In the alternative, the venting catheter 54 may be provided withmeans on the exterior thereof, such as expanded coils as described inU.S. Pat. No. 4,889,137 (Kolobow), which hold open the tricuspid andpulmonary valves and perform the same function of decompressing the leftatrium. See also the article written by F. Rossi et. al. in the Journalof Thoracic Cardiovascular Surgery, 1900;100:914-921, entitled“Long-Term Cardiopulmonary Bypass By Peripheral Cannulation In A ModelOf Total Heart Failure”, which is incorporated herein in its entirety byreference.

The operation of the cardiopulmonary by-pass unit 18 is initiated towithdraw blood from the femoral vein 16 through catheter 17, remove CO₂from and add oxygen to the withdrawn blood and then pump the oxygenatedblood through the return catheter 19 to the right femoral artery 15. Theballoon 11 may then be inflated to occlude the ascending aorta 12,causing the blood pumped out of the left ventricle (until the heartstops beating due to the cardioplegic fluid as discussed hereinafter) toflow through the discharge port 41 into the first inner lumen 40 of theoccluding catheter. The blood flows through the inner lumen 40 and outthe third arm 32 of the adapter 26 into the by-pass line 33 and theninto the blood filter and blood recovery unit 37 through the valve 34and line 36. For blood and irrigation fluids containing debris and thelike, the position of the valve 34 may be changed to direct the fluidthrough the discharge line 35.

The balloon 47 on the distal extremity of the retroperfusion catheter 20is inflated to occlude the coronary sinus 21 to prevent fluid lossthrough the discharge opening 46 into the right atrium 45. A liquidcontaining a cardioplegic agent such as KCl is directed through thecatheter 20 into the coronary sinus 21 and the pressure of thecardioplegic fluid within the coronary sinus 21 is maintainedsufficiently high, (e.g. 40 mm Hg) so that the cardioplegic fluid willpass through the coronary veins, crossing the capillary beds to thecoronary arteries 50 and 51 and out the ostia 52 and 53. However,cardioplegic fluid pressure is not increased far above 75 mm Hg. Oncethe cardioplegic fluid passes through the capillary beds in themyocardium, the heart very quickly stops beating. At that point themyocardium is paralyzed and has very little demand for oxygen and can bemaintained in this state for long periods of time with minimal damage.

With the cardiopulmonary by-pass system in operation, the heartcompletely paralyzed and not pumping, the left atrium decompressed andthe ascending aorta blocked by the inflated balloon 11 on the occludingcatheter 10, the heart is appropriately prepared for a cardiacprocedure.

Inflation of the inflatable member 11 on the distal end of the deliverycatheter 10 fixes the distal end of the occluding catheter 10 within theascending aorta 12 and isolates the left ventricle 13 and the upstreamportion of the ascending aorta from the rest of the arterial systemdownstream from the inflatable member. The passage of any debris oremboli, solid or gaseous, generated during a cardiovascular procedure toregions downstream from the site would be precluded by the inflatedballoon 11. Fluid containing debris or emboli can be removed from theregion between the aortic valve and the occluding balloon 11 through theinner limen 40 of catheter 10. A clear, compatible fluid, e.g. anaqueous based fluid such as saline delivered through the inner lumen 40or the cardioplegic fluid discharging from the coronary ostia 52 and 53,may be maintained in the region wherein the cardiovascular procedure isto be performed to facilitate use of an angioscope or other imagingmeans that allows for direct observation of the cardiac procedure.Preferably, the fluid pressure in the left ventricle 13 is maintainedsufficiently higher than that in the left atrium to prevent blood fromthe left atrium from seeping into the left ventricle and interferingwith the observation of the procedure. The inner lumen 40 is dimensionedto allow for the passage of instruments used during the cardiacprocedure such as a tissue cutter, an angioscope, and tubes used forinfusing irrigation fluid and for aspirating debris, thrombus and thelike, and for the introduction of a prosthetic device, such as a heartvalve.

Additional exemplary embodiments of the cardiac access system of theinvention are illustrated in FIGS. 16-24. The heart 210 of FIGS. 16 and17 is positioned in the living body of a patient and is accessedpercutaneously.

In order to induce cardioplegia in the heart while maintaining thepatient it is necessary to divert the patient's blood circulationthrough an extracorporeal cardiopulmonary by-pass system. This isachieved by isolating the heart 210 on both the venous and arterialsides using appropriate percutaneously inserted venous catheter 211,aortic balloon catheter 212, and if this catheter 212 doesn't haveprovision for arterial blood return, arterial catheter 239 (see FIG.18). The venous outflow and arterial inflow lumina of the catheters 211and 212 of the by-pass system are of sufficient cross sectional area toachieve standard blood flows to maintain the patient's systemiccirculation during the period of extracorporeal circulation.

In the case of the use of a single venous double-ballooned catheter 211,as is shown in FIG. 16, the catheter 211 is inserted through the femoralvein preferably. A suitable guide wire is initially inserted and thecatheter 211 is then introduced in known manner under fluoroscopicguidance. The catheter 211 includes a pair of separately inflatableballoons 214 and 215 each connected to a balloon inflation controldevice (not shown) through suitable lumina in the catheter 211. Theballoon 214 is adapted to occlude the superior vena cavae 216 while theballoon 215 is adapted to occlude the suprahepatic inferior vena cavae217. A blood withdrawal lumen in the catheter 211 has an inlet orifice218 flush with the balloon 214, to avoid venous collapse during bloodflow into the catheter 211, and a series of inlet slots 219 in theinferior vena cavae. Blood drawn into the inlets 218 and 219 enters acommon single lumen. Blood drawn into the by-pass system through thecatheter 211 is oxygenated and returned to the patient in a manner whichwill be hereinafter described.

A separate lumen in the catheter 211 opens into the right atrium 222through aperture 221 to allow evacuation of blood from the right heartand the infusion of saline to induce topical cooling and/or to improvevisual acuity within the right heart.

In use, after the catheter 211 has been positioned the balloons may beinflated or deflated to vary the rate of venous return to the rightatrium 222 and therefore the degree of decompression of the left heart.Venous drainage may be effected by gravitational drainage or by applyinga degree of negative pressure to assist flow into the pump oxygenator.It will be appreciated that the distance between the balloons 214 and215 will need to be correct for a given patient and this may be assessedby X-ray examination to allow selection of an appropriately sizedcatheter. Alternatively separate catheters 211 b and 211 c could beused, as is shown in FIG. 24 a, for the inferior and superior venacavae. The cannula 211 b being introduced as has been described aboveand the cannula 211 c being introduced through the jugular or subclavianvein. It will also be appreciated that for simple operations notrequiring complete occlusion of the right atrium it is possible tomerely insert a simple catheter 211 into the right atrium to draw bloodinto the by-pass system as is seen in FIG. 17. Positioning underfluoroscopic guidance is not essential in this case.

The catheter 212 is positioned in the manner described above with itsfree end located in the ascending aorta 223. The catheter 212 is sopositioned by insertion preferably through the femoral artery 224 andvia the descending aorta 225 as is seen in FIG. 18.

If desired a fluoroscopic dye may be introduced into the aortic root 226through the catheter 212 for accurate positioning of the tip of thecatheter 212 relative to the aortic root 226 and the coronary ostia.

The catheter 212 carries at its free end a balloon 227. The balloon 227is arranged to be inflated with saline from an inflation control device228 of known type through a lumen in the catheter 212. The device 228 isfitted with a pressure gauge 229 to allow the operator to control theinflation of the balloon 227. The pressure of the fully inflated balloon227 should be of the order of 350 mmHg so as to be sufficient toeffectively occlude the aorta and to prevent the balloon moving whilenot being so great as to cause damage to the aortic wall. The balloon227 should have a maximum diameter sufficient to occlude the aorta andfor this purpose the maximum diameter should be about 35 mm. The balloon227 should have a length of about 40 mm so as not to be so long as toocclude or impede blood flow to the coronary arteries or to thebrachiocephalic, subclavian or carotid arteries. If necessary in anygiven patient the required length and diameter of the balloon may bedetermined by angiographic, X-ray examination or echocardiography and anappropriately sized catheter selected on that basis.

The balloon 227 is preferably connected to the lumen 232 through whichit is inflated at the end of the balloon 227 distal to the tip of thecatheter 212 through orifice 231 (see FIG. 20). This allows the tip ofthe catheter to contain fewer lumina than the remainder of the catheter.Accommodation of the deflated balloon around the tip of the catheter isthus possible without adding to the diameter of the tip as compared withthe rest of the catheter 212.

The catheter 212 includes a plurality of lumina (see FIGS. 21 and 22).In addition to the balloon inflation lumen 232 there is at least asingle venting/cardioplegia lumen 233 of circular cross-section. Theremay be a separate and extra circular lumen 234 for instrumentation. Iftwo lumens are present the venting/cardioplegia lumen may be circular orcrescent shaped in cross-section (FIG. 21 a, 21 b). The diameter of thevarious lumina should be as small as practicable commensurate with theintended use. In addition, there may be a continuous lumen 235 throughwhich arterial blood is returned from the by-pass. This may flow out ofthe catheter 212 through an orifice in the region of the external iliacartery. In alternative embodiments of the invention such as shown inFIGS. 18 and 23 b the arterial return lumen 235 may comprise its owncatheter 239 of known type introduced into the other femoral artery orsome other suitable artery.

In use the catheter 212 is introduced percutaneously by puncture orcutdown as has been described and once blood flow through the by-pass isestablished (including systemic cooling) flows are reduced and theballoon 225 is inflated. Flows are then returned to the operating levelsand a suitable cardioplegic agent is introduced into the aortic root.Once the full volume of cardioplegic agent has been given and cardiacarrest achieved, the lumen is then used to vent the heart. The heart maythen be operated on or examined by insertion of instrumentation 237 suchas a cardioscope or a laser into the heart through the lumen 234 orthrough thoracic and/or atrial trocars. Alternatively, with the heart onby-pass as described above the heart can be approached by an open methodby an incision other than median sternotomy. Venting of the leftventricle may be effected by providing an extended cannula 238projecting from lumen 233 into the left ventricle (see FIG. 17) or bysimply applying negative pressure to the venting lumen 233 of the aorticcatheter. To reverse cardioplegic arrest the body is rewarmed and theballoon 227 deflated. Aortic blood is thus allowed to perfuse the heart.Whilst the body remains supported by peripheral cardiopulmonary by-pass,the return of the heart rhythm is awaited. External defibrillation maybe necessary. Weaning from by-pass is then completed in a routinefashion.

The cardiac accessing system of the invention is particularly useful inthe removal of the aortic heart valve and replacement thereof with aprosthetic heart valve which is illustrated in FIGS. 5 through 8. Asshown in FIG. 5, a tissue cutter 65 is inserted into the patient throughthe inner lumen 40 of the occluding catheter 10 and advanced therein tothe site of the aortic valve 66 which is to be removed. An angioscope 67is likewise advanced through the inner lumen 40 until the distal endthereof extends out of the distal end of the occluding catheter 10. Atleast one of the cutting blades 68 and 69 on the tissue cutter 65 isactuated from the proximal end thereof which extends out of the secondarm 30 of the adapter 26 on the proximal end of the catheter 10. Theguidance and operation of the cutter 65 is controlled by the physicianor other operator while observing the cutter through the angioscope 67.Due to its size and condition, the aortic valve 66 will usually have tobe cut into smaller sections, such as section 70 as shown, so that itwill fit within the inner lumen 40 of the occluding catheter 10 in orderto remove the valve material from the patient. Preferably, forceps 71 orother suitable grasping means are employed to hold onto the aortic valvesections as they are severed by the cutting means 65 to ensure that thevalve sections are accurately severed from the site with little or nodamage to the underlying tissue of the ascending aorta and removedthrough the inner lumen 40. The cutting means 65 may have to bewithdrawn from the occluding catheter 10 before large severed portionsof the aortic valve 66 can be removed by forceps 71. During theprocedure a continuous flow of clear liquid, such as the clearcardioplegic fluid exiting the ostia 52 and 53 and/or fluid beinginfused via the clamp 10 or an angioscope 67, is maintained tofacilitate the observation of the region by the operator using theangioscope 67. After the valve 66 has been severed and removed from theregion, the instruments used for this particular procedure are withdrawnfrom the patient through the inner lumen 40 of the occluding catheter10. Instead of or in addition to mechanical cutting means, laser,electrosurgery, or other cutting methods may be employed in the valveremoval procedure.

Direct observation of the placement of the cutting device 65 by suitableimaging means such as an angioscope 67 will ensure accurate positioningof the cutter blades 68 and 69 against the aortic valve to moreeffectively sever the valve 66 with little or no damage to thesupporting aortic tissue. Aortic damage might interfere with theplacement of a replacement valve 72 at the site. The precision of thevalve removal and replacement is important to the success ofendovascular valve replacement. There are several imaging techniquespresently available, in addition to the angioscopic technique described,which provide complementary options to assure this precision, namely 1)transesophageal echocardiography; 2) intravascular ultrasound passedthrough the inner lumen of the delivery catheter 10; 3) intravascularultrasound or angioscopy passed intravascularly via the venous systemthrough the intra-atrial septum, across the mitral valve, and into theleft ventricle; and 4) fluoroscopy. Note that an angioscope within theleft ventricle would provide both the added benefit of allowing constanthigh definition imaging of the entire procedure and high-flowirrigation.

After the heart valve 66 is removed, a replacement valve 72 is thenadvanced through the inner lumen 40 of the occluding catheter 10 asshown in FIG. 6. The valve 72 is preferably a bioprosthetic valve suchas xenograft valve. Porcine glutaraldehyde preserved valves are quitesuitable because, as previously mentioned, they are readily accessible,they are storable, and they are available in a variety of sizes. Thereplacement valve 72, which is shown in FIG. 6 in an inverted and foldedcondition, has a Dacron skirt 73 secured to the lower rim of the naturalporcine valve to facilitate securing the replacement valve to the wallof ascending aorta 12 at or near to the site from which the originalaortic valve 66 was removed. The folded and inverted replacement valve72 is disposed within the expanded end 74 of valve delivery catheter 75so that the valve 72 can be advanced through the occluding catheter 10.The valve 72 is urged out of the expanded end 74 by the connector cables84 which are connected to the upper extensions of the valve byreleasable means 83. Once outside of the expanded end 74, the valve 72expands due to the natural resiliency of the valve and the connectorcables. The valve delivery catheter 75 is then removed by withdrawing itthrough the inner lumen 40 of the occluding catheter 10. Alternatively,the valve 72 may be provided with a temporary or permanent expandablesupport frame. The frame may contain stapling elements to secure thevalve to the aortic wall.

The Dacron skirt 73 is fixed to the aortic root 12 by means of aplurality of U-shaped staples 76, as shown in FIG. 7, which are securedby the stapling mechanism 77 which is advanced through the inner lumen40 and out of the distal port 41. The stapling mechanism 77 has anL-shaped holding arm 78 that holds the staple 76 and shaping member 79having an arcuate shaping surface 80 which presses the staple 76 againstholding arm 78 deforming the staple as it is pushed through the Dacronskirt 73 and into the aortic wall 81 as shown to force the pointed armsor tines thereof toward each other and fix the staple within the aorticwall. In the alternative the holding arm 78 may be moved toward theshaping member 79 or both may be advanced toward each other. Thestapling mechanism 77 is preferably provided with a removable protectivesheath (not shown) to facilitate the advancement of the mechanismthrough the inner lumen 40 without the pointed ends or tines of thestaples 76 sticking into the inner wall of the occluding catheter 10which defines the inner lumen 40. Usually about 10 to about 20 stapleswill be required to adequately secure the skirt 73 to the aortic wall81. The angioscope 67 is provided to allow the physician to observe theprocedure and guide the stapling mechanism 77 to the desired locationand to secure the staple 76 and the skirt 73 at the desired locationwithin the aortic root 12.

Once the Dacron skirt 73 is properly secured, the inverted valve 72 ispulled through the fixed Dacron skirt 73, as shown in FIG. 8, and theupper extensions of the new valve 72 are stapled in essentially the samemanner as the Dacron skirt 73. Care must be exercised when placing theDacron skirt 73 prior to securing it to the aortic wall 81 so that whenthe inverted portion of the new valve 72 is pulled through the securedDacron skirt 73, the ostia 52 and 53 of the coronary arteries 50 and 51are not blocked by the upper extensions 82 of the valve 72. After theupper extensions 82 are secured to the aortic wall 81, the releasablemeans 83 at the end of the connector cables 84 are released and thecables are withdrawn through the inner lumen 40 of the occludingcatheter 10.

Any tissue debris resulting from the aortic valve removal and new valveplacement is trapped by the barrier formed by the inflated balloon 11 onthe distal end of the occluding catheter 10. However, liquid in theaortic region containing such debris may be removed through anaspiration tube (not shown) disposed within the inner lumen 40 of theoccluding catheter 10 or through inner lumen 40 by aspirating the fluidcontaining the debris. An irrigation catheter may be used to dislodgeany debris caught between the inflated balloon 11 and the aortic wallwhere the two meet.

When the replacement valve 72 is secured in place, the fluid pumpedthrough the retroperfusion catheter 20 is changed to a compatible fluid,e.g. saline or blood, containing no cardioplegic agents in order toflush out the cardioplegic materials from the myocardium through theostia 52 and 53. The pulmonary venting catheter 54 may also be removedat the same time. Shortly thereafter the heart begins to beat on its ownor it is externally defibrillated and the blood coming into the rightheart is pumped through the pulmonary trunk to the lungs where it isoxygenated in the normal fashion. Oxygenated blood is returned from thelungs into the left atrium and is then pumped from the left ventriclethrough the new valve into the ascending aorta. Initially, the balloon11 is maintained in the inflated condition, forcing the blood pumped outof the left ventricle to pass through the region of the ascending aorta12 into inner lumen 40 of the occluding catheter 10 taking with itdebris, emboli and the like. The blood passing through inner lumen 40 isdirected through the third arm 32 of adapter 26, through the valve 34and line 36 leading to blood filter and recovery unit 37 where the bloodmay be filtered and returned to the patient through the cardiopulmonaryby-pass system 18. Alternatively, the position of the valve 34 may bechanged by means of arm 85 to discharge blood or other fluid containingtissue, emboli, debris and the like through discharge line 35. Aftersufficient time has elapsed to ensure that debris and embolus freeoxygenated blood is being pumped out of the left ventricle 13 theballoon 11 is deflated to allow natural blood flow through the aorta andthe cardiopulmonary by-pass system 18 is shut down.

The occluding catheter shaft 39 may be formed of conventional materialssuch as polyethylene, polyvinyl chloride and the like. Balloon 11 may beformed of materials such as latex, silicone, C-Flex, or the like.Preferably, the balloon 11 is elastic, so as to expand to andcircumferentially occlude the vessel into which it is positioned whenfluid pressure is applied to the balloon. Alternatively, the balloon 11may be formed of polymers such as polyethylene, polyethyleneterephthalate, or a polyolefinic ionomer such as Surlyn®, which isavailable from E.I. DuPont, DeNemours & Co. Such a balloon would berelatively inelastic when inflated, so as to inflate to a predeterminedsize and maintain essentially that size even when additional fluidpressure is applied within the interior of the balloon. The balloon 11will generally have an expanded diameter of about 20 to 40 mm toeffectively occlude the patient's ascending aorta and an expanded lengthof about 2 to about 10 cm so as to be disposed between the coronaryostia and the brachiocephalic artery without blocking these arteries.The overall length of the occluding catheter should be at least 80 cm tofacilitate passage through the femoral or brachiocephalic arteries tothe ascending aorta.

The retroperfusion catheter 20 may be a commercially availableretroperfusion catheter. There are suitable cardiopulmonary by-passsystems available commercially. For a brief discussion ofcardiopulmonary by-pass systems reference is made to Weber, John G.,Encyclopedia of Medical Devices and Instrumentation, Vol. 3, pp.1440-1457.

An alternative tissue cutting system is depicted in FIGS. 9 and 10. Inthis embodiment catheter 90 is provided with a cutting head 91 which isslidably disposed within the cutter housing 92. The cutting head 91 isprovided with a cutting edge 93 and cutter housing 92 is provided withcutting edge 94. The distal end of the catheter 90 is urged againsttissue which is to be removed so that the tissue is pressed into thereceiving chamber 95 within the cutting head 91. The cutting head 91 isslidably withdrawn from the cutter housing 92 so that the cutting edge93 slides by the cutting edge 94 in a cutting relationship so as tosever the tissue within the receiving chamber 95. The severed tissue maybe removed by aspiration or the cutting head 91 may be withdrawn fromthe patient and the severed tissue may be manually or otherwise removed.Preferably, the positioning of the distal end of catheter 90 and theurging of the cutting head against the tissue to be removed is observedby the physician or other operator through angioscope 67 or othersuitable imaging system as previously described.

Another cutting system 96, which is shown in FIG. 11, has expandablecutting blades 97 and 98 which are biased or otherwise adapted to expandto a cutting position as shown and rotated at high rotational speeds bya drive shaft and then pressed against the tissue to be severed. Theblades 97 and 98 may be biased to expand outwardly by a spring (notshown) or the blades may be forced outwardly by the high speed rotationthereof. This cutting operation is likewise preferably observed by thephysician or other operator to ensure proper cutting of the tissue to beremoved.

An alternative valve introducer device 100 is shown in FIGS. 12-13 whichis adapted to contain a prosthetic or replacement valve 101 withinexpanded distal portion 102. The introducer device 100 may be introducedby itself or through the inner lumen of the occluding delivery cathetersuch as previously described until the enlarged distal portion 102 islocated at or extends out of the distal end of the delivery catheter.The valve introducer device 100 may be provided with one or morepositioning balloons 103 surrounding the expanded distal end 102 thereofwhich may be inflated in a differential manner, to assure accuratepositioning of a prosthetic valve 101 when delivered out of the expandeddistal end. A means, such as piston 104 is provided to push thereplacement valve 101 out of the expanded distal end 102 when it is inthe appropriate position within the patient's ascending aorta. Forcepsor other holding means as previously described may be used to positionthe replacement valve 101 within the location from which the originalvalve has been removed.

An alternative replacement or prosthetic valve 101 is best shown in theexpanded condition in FIGS. 14 and 15. As indicated, the valve 101 isprovided with a cylindrical base 105 having mounting staples 106 whichcan be pressed into the wall portion of the ascending aorta at thedesired situs by means of an expandable inelastic balloon 107 which isinflated within the valve 101. The upper extensions 108 of thereplacement valve 101 from which the leaves or cusps 109 are supportedare for the most part self supporting and may not require securing tothe wall section of the ascending aorta. The valve introducer device 100and the inflatable balloon 107 which when inflated presses the mountingstaples 106 into the aortic wall may, when deflated, be withdrawnthrough the inner lumen of a delivery catheter. The aortic regionbetween the site of the replacement valve and the delivery catheter maybe well irrigated to remove debris, emboli and the like before regularblood flow through the region is resumed.

The invention provides several benefits, including the ability toendovascularly replace existing cardiac valves or perform other cardiacprocedures while avoiding the riskier, more expensive and more traumaticopen-heart surgical procedure.

The replacement prosthetic valve device is preferably a bioprostheticdevice because these valves do not require the patient to undertakelife-long anticoagulant therapy as do mechanical valves. Once inserted,the bioprosthetic valve is capable of operating autonomously. The usefullife of a bioprosthetic valve placed via the endovascular procedure mayextend to over twenty years, and since most of the valve procedures areperformed on the elderly, the bioprosthetic valve will usually functionwell throughout the remaining life of the patient.

Once the endovascular implantation of the prosthetic valve device iscompleted in the patient, the function of the prosthetic valve devicecan be monitored by the same methods as used to monitor valvereplacements done by open-heart surgery. Routine physical examination,angiography, or periodic echocardiography can be performed. In contrastto open-heart surgery, however, the patient will recover in a very shortperiod when his or her aortic valve is endovascularly removed andreplaced with a prosthetic valve. The replacement valve device can beused in any patient where bioprosthetic valves are indicated, and isparticularly suitable for elderly patients and patients unable totolerate open-heart procedures or life-long anticoagulation.

Unless described otherwise, the various components of the system of thepresent invention can be formed of conventional materials usingconventional manufacturing techniques. The dimensions of the variouscomponents are selected so that they perform their intended functions intheir intended environment.

Turning now to FIGS. 25-40, several additional exemplary embodiments ofan endovascular device for partitioning the ascending aorta according tothe invention will be described. As illustrated in FIG. 25, partitioningdevice 320 includes a shaft 322 having a distal end 324 and a proximalend 326. An expandable means 328 for occluding the ascending aorta ismounted to shaft 322 near distal end 324. In a preferred embodiment,occluding means 328 comprises a polymeric balloon 330 (shown inflated)of a material, geometry, and dimensions suitable for completelyoccluding the ascending aorta to block systolic and diastolic bloodflow, as described more fully below.

Shaft 322 has a diameter suitable for introduction through a femoral oriliac artery, usually less than about 9 mm. The length of shaft 322 ispreferably greater than about 80 cm, usually about 90-100 cm, so as toposition balloon 330 in the ascending aorta between the coronary ostiaand the brachiocephalic artery with proximal end 326 disposed outside ofthe body, preferably from the femoral or iliac artery in the groin area.Alternatively, the shaft may be configured for introduction through thecarotid artery, through the brachial artery, or through a penetration inthe aorta itself, wherein the shaft may have a length in the range of 20to 60 cm.

Partitioning device 320 further includes a first inner lumen 329, shownin FIGS. 26A-26B, extending between proximal end 326 and distal end 324with an opening 331 at distal end 324. Additional openings incommunication with inner lumen 329 may be provided on a lateral side ofshaft 322 near distal end 324.

Shaft 322 has a shaped distal portion 332 configured to conformgenerally to the curvature of the aortic arch such that opening 331 atdistal end 324 is spaced apart from the interior wall of the aorta andis axially aligned with the center of the aortic valve. Usually, shapeddistal portion 332 will be generally U-shaped, such that a distalsegment 334 is disposed at an angle between 135° and 225°, andpreferably at approximately 180° relative to an axial direction definedby the generally straight proximal segment 336 of shaft 322. Shapeddistal portion 332 will usually have a radius of curvature in the rangeof 20-80 mm (measured at the radial center of shaft 322), depending uponthe size of the aorta in which the device is used. The configuration ofshaped distal portion 332 allows distal segment 334 to be positionedcentrally within the lumen of the ascending aorta and distal end 324 tobe axially aligned with the center of the aortic valve, therebyfacilitating infusion or aspiration of fluids as well as introduction ofsurgical tools through opening 331 without interference with the wall ofthe aorta, as described more fully below.

In an exemplary embodiment, shaped distal portion 332 is preshaped so asto maintain a permanent, generally U-shaped configuration in anunstressed condition. Such a preshaped configuration may be formed bypositioning a mandrel having the desired shape in first inner lumen 329,then baking or otherwise heating shaft 322 and the mandrel for asufficient time and sufficient temperature to create a permanent settherein, e.g., 1-3 hours at a temperature in a range of 120_C to 180_C,depending upon the material used for shaft 322.

Alternative embodiments of shaped distal portion 332 are illustrated inFIGS. 25B and 25C. In the embodiment of FIG. 25B, U-shaped distalportion 332, rather than having a continuous, constant curvature, ispreshaped in a more angular fashion, with bends 333 of relatively smallcurvature separating segments 335 which are either straight or of largercurvature. Bends 333 and/or segments 335 may further be configured toengage the inner wall of the aortic arch to deflect distal end 324 intoa desired position in the ascending aorta.

In the embodiment of FIG. 25C, shaped distal portion 332 is configuredin a general “S” shape for introduction into the ascending aorta from alocation superior to the aortic arch. In this way, distal segment 334may be positioned within the ascending aorta, with proximal segment 336extending from the aortic arch through the brachiocephalic artery to thecarotid or brachial artery, or through a penetration in the aortaitself, to a point outside of the thoracic cavity.

As shown in FIG. 25A, distal segment 334 may be skewed (non-coplanar)relative to a central longitudinal axis of proximal segment 336, inorder to further conform to the shape of the patient's aortic arch andalign with the center of the aortic valve. In an exemplary embodiment,distal segment 334 is disposed at an angle α relative to a planecontaining the central axis of proximal portion 336, wherein α isbetween 2° and 30°, usually between 10° and 20°, and preferably about15°. The shape and dimensions of shaped distal portion 332 and angle αof distal segment 334 may vary, however, according to the configurationof the aortic arch in any individual patient.

In a preferred embodiment, the device will include a soft tip 338attached to distal end 324 to reduce the risk of damaging cardiactissue, particularly the leaflets of the aortic valve, in the event thedevice contacts such tissue. Soft tip 338 may be straight or tapered inthe distal direction, with an axial passage aligned with opening 331 atthe distal end of shaft 322. Preferably, soft tip 338 will be a lowdurometer polymer such as polyurethane or Pebax, with a durometer in therange of 65 Shore A to 35 Shore D.

At least one radiopaque stripe or marker 339 is preferably provided onshaft 322 near distal end 324 to facilitate fluoroscopic visualizationfor positioning balloon 330 in the ascending aorta. Radiopaque marker339 may comprise a band of platinum or other radiopaque material.Alternatively, a filler of barium or bismuth salt may be added to thepolymer used for shaft 322 or soft tip 338 to provide radiopacity.

As illustrated in FIGS. 25, 26A and 26B, a straightening element 340 isdisposed in first inner lumen 329 of shaft 322 so as to slidelongitudinally relative to the shaft. Straightening element 340 maycomprise a tubular stylet with a longitudinal passage 344 for receivinga guidewire 342, as described below. Alternatively, element 340 maycomprise a relatively stiff portion of the guidewire itself.Straightening element 340 may be a polymeric material or a biocompatiblemetal such as stainless steel or nickel titanium alloy with a bendingstiffness greater than that of shaft 322. In this way, straighteningelement 340 may be advanced distally into preshaped distal portion 332so as to straighten shaft 322, facilitating subcutaneous introduction ofpartitioning device 320 into an artery and advancement to the aorticarch. Straightening element 340 may then be retracted proximallyrelative to the shaft so that distal end 324 can be positioned in theascending aorta with preshaped distal portion 332 conforming to theshape of the aortic arch.

A movable guidewire 342 is slidably disposed through first inner lumen329, either through longitudinal passage 344 in straightening element340 (FIG. 26B), external and parallel to straightening element 340, orthrough a separate lumen (not shown) in shaft 322. Guidewire 342 extendsthrough opening 331 in distal end 324 of shaft 322 and may be advancedinto an artery distal to shaft 322, facilitating advancement of shaft322 through the artery to the ascending aorta by sliding the shaft overthe guidewire. In an exemplary embodiment, guidewire 342 is relativelystiff so as to at least partially straighten shaft 322, so thatstraightening element 340 is unnecessary for introduction of shaft 322.In this embodiment, guidewire 342 may be, for example, stainless steelor a nickel titanium alloy with a diameter of about 1.0 mm to 1.6 mm.

Shaft 322 may have any of a variety of configurations depending upon theparticular procedure to be performed. In one embodiment, shaft 322 has amulti-lumen configuration with three non-coaxial parallel lumens in asingle extrusion, as illustrated in FIGS. 26A, 27 and 29A. The threelumens include first inner lumen 329, which receives straighteningelement 340 and guidewire 342 and includes opening 331 at its distalend, an inflation lumen 346 which opens at an inflation orifice 347(FIG. 27) near the distal end of shaft 322 in communication with theinterior of balloon 330, and a third lumen 348 which has an opening (notshown) at distal end 324 of the shaft to sense pressure in the ascendingaorta upstream of balloon 330. In this embodiment, the largesttransverse dimension of first inner lumen 329 is preferably about 1 mm-4mm. Advantageously, the distal opening in third lumen 348 is radiallyoffset from opening 331 in first inner lumen 329, so that infusion oraspiration of fluid through first inner lumen 329 will not affectpressure measurements taken through third lumen 348.

In a second embodiment, illustrated in FIG. 29B, shaft 322 has a duallumen inner member 350 and a coaxial outer member 352. Inner member 350includes first inner lumen 329 which receives straightening element 340and opens at distal opening 331, and a third lumen 354 which has anopening (not shown) at its distal end for measuring pressure in theascending aorta. Outer member 352 defines a coaxial inflation lumen 356which, at its distal end, is in communication with the interior ofballoon 330. Balloon 330 and outer member 352 may comprise a singleintegrated extrusion, or balloon 330 may be bonded or otherwise attachedto outer member 352 near the distal end of shaft 322 using well-knowntechniques. Outer member 352 may have an open distal end whichcommunicates with the interior of balloon 330. Alternatively, the distalend of outer member 352 may be closed, for example, by bonding to theexterior of inner member 350, with an inflation orifice 347 provided asshown in FIG. 26A for communication between lumen 356 and the interiorof the balloon.

In a third embodiment, illustrated in FIGS. 26B, 28 and 30, shaft 322has a first inner lumen 329 of large diameter configured to receivevarious types of surgical instruments, as well as to receivestraightening element 340. An inflation lumen 358 extends parallel tofirst inner lumen 329 and is in communication with the interior ofballoon 330 through an inflation orifice 361, shown in FIG. 26B. In thisembodiment, shaft 322 may comprise a single extrusion containinginflation lumen 358 and inner lumen 329, or two individual tubes bondedto one another, one tube containing lumen 329 and the other containinginflation lumen 358. With this construction, shaft profile can beminimized while making lumen 329 as large as possible within theconfines of the vessels in which the device is positioned. In thisembodiment, first inner lumen 329 will have a diameter of at least about5 mm and preferably about 8 mm. Partitioning device 320 thereby providesa passage of maximum diameter for endovascular introduction of surgicalinstruments such as visualization scopes, aspirators, irrigation tubes,cutting, stapling and suturing devices, and the like.

It should be noted that where partitioning device 320 is to be utilizedfor antegrade delivery of cardioplegic fluid through first inner lumen329, it will be configured to provide a sufficient flowrate of suchfluid to maintain paralysis of the heart, while avoiding undue hemolysisin the blood component (if any) of the fluid. In a presently preferredembodiment, cold blood cardioplegia is the preferred technique forarresting the heart, wherein a cooled mixture of blood and a crystalloidKCl/saline solution is introduced into the coronary arteries to perfuseand paralyze the myocardium. The cardioplegic fluid mixture ispreferably run through tubing immersed in an ice bath so as to cool thefluid to a temperature of about 3_C-10_C prior to delivery through innerlumen 329. The cardioplegic fluid is delivered through inner lumen 329at a sufficient flowrate and pressure to maintain a pressure in theaortic root (as measured through third lumen 348) high enough to induceflow through the coronary arteries to perfuse the myocardium. Usually, apressure of about 50-100 mmHg, preferably 60-70 mmHg, is maintained inthe aortic root during infusion of cardioplegic fluid, although this mayvary somewhat depending on patient anatomy, physiological changes suchas coronary dilation, and other factors. At the same time, in pumpingthe cardioplegic fluid through inner lumen 329, it should not be subjectto pump pressures greater than about 300 mmHg, so as to avoid hemolysisin the blood component of the fluid mixture. In an exemplary embodiment,first inner lumen 329 is configured to facilitate delivery of thecardioplegic fluid at a rate of about 250-350 ml/min. preferably about300 ml/min., under a pressure of no more than about 300 ml/min, enablingthe delivery of about 500-1000 ml of fluid in 1-3 minutes. To providethe desired flowrate at this pressure, inner lumen 329 usually has across-sectional area of at least about 4.5 mm², and preferably about5.6-5.9 mm². In an exemplary embodiment, D-shaped lumen 329 in FIG. 29Ahas a straight wall about 3.3 mm in width, and a round wall with aradius of about 1.65 mm. A completely circular lumen 329 (not pictured),could have an inner diameter of about 2.7 mm. Inner lumen 329 could besignificantly smaller, however, if the cardioplegic fluid did not have ablood component so that it could be delivered under higher pressureswithout risk of hemolysis. Because of its myocardial protective aspects,however, the forementioned blood/KCl mixture is presently preferred,requiring a somewhat larger lumen size than would be required for acrystalloid KCl cardioplegic fluid without blood.

In some embodiments, as shown in FIGS. 26B, 28 and 30, a wire braid orcoil 360 may be embedded in the wall of shaft 322 to enhance radialrigidity and to maintain the transverse dimensions of first inner lumen329. It is particularly important to maintain the roundness of firstinner lumen 329 where surgical tools are to be introduced through thefirst inner lumen. If shaft 322 is made of sufficient diameter toaccommodate such tools through lumen 329, the shaft may tend to flattenor kink when advanced into the curved region of the aortic arch. The useof wire braid or coil 360 to maintain lumen roundness allows toolprofile to be maximized and allows tools to be advanced through thelumen with minimum interference. Wire braid or coil 360 may be formed ofstainless steel or other biocompatible material such as nickel titaniumalloy, aramid fibers such as Kevlar™ (DuPont), or nylon.

Shaft 322 may be constructed of any of a variety of materials, includingbiocompatible polymers such as polyurethane, polyvinyl chloride,polyether block amide, or polyethylene. In a preferred embodiment of thedevice shown in FIG. 26A, shaft 322 is urethane with a shore durometerin the range of 50D-80D. In the embodiment of FIG. 26B, wherein shaft322 may have a significantly larger diameter as well as an embedded coilwhich both increase stiffness, a polyurethane with shore durometer of60A-100A may be used. Shaft 322 may have a bending modulus in the rangeof 70 to 100 kpsi, preferably about 80-90 kpsi. A bending modulus inthis range provides sufficient stiffness to optimize pushability from afemoral or iliac artery to the ascending aorta, while providingsufficient flexibility to navigate the tortuous iliac artery and theaortic arch. Once partitioning device 320 has been positioned withdistal end 324 in the ascending aorta, this bending modulus alsofacilitates exertion of a distally-directed force on shaft 322 fromproximal end 326 to maintain the position of balloon 330 against theoutflow of blood from the left ventricle as the balloon is inflated. Inother embodiments, the dimensions, geometry and/or materials of shaft322, as well as coil 360, may be varied over the length of the shaft sothat the shaft exhibits variable bending stiffness in various regions.For example, preshaped distal portion 332 may be more flexible fortracking through the aortic arch, whereas proximal portion 336 may bestiffer for pushability and resistance to displacement.

Balloon 330 may be constructed of various materials and in variousgeometries. In a preferred embodiment, balloon 330 has a collapsedprofile small enough for introduction into the femoral or iliac artery,e.g. 4-9 mm outside diameter, and an expanded (inflated) profile largeenough to completely occlude the ascending aorta, e.g. 20-40 mm outsidediameter. The ratio of expanded profile diameter to collapsed profilediameter will thus be between 2 and 10, and preferably between 5 and 10.The balloon is further configured to maximize contact of the workingsurface of the balloon with the aortic wall to resist displacement andto minimize leakage around the balloon, preferably having a workingsurface with an axial length in the range of about 3 cm to about 7 cmwhen the balloon is expanded. Textural features such as ribs, ridges orbumps may also be provided on the balloon working surface for increasedfrictional effects to further resist displacement.

Balloon 330 preferably has some degree of radial expansion or elongationso that a single balloon size may be used for aortas of variousdiameters. Materials which may be used for balloon 330 includepolyurethanes, polyethylene terephthalate (PET), polyvinyl chloride(PVC), polyolefin, latex, ethylene vinyl acetate (EVA) and the like.However, balloon 330 must have sufficient structural integrity wheninflated to maintain its general shape and position relative to shaft322 under the systolic pressure of blood flow through the ascendingaorta. In an exemplary embodiment, balloon 330 is constructed ofpolyurethane or a blend of polyurethane and polyvinyl such as PVC. Ithas been found that such materials have sufficient elastic elongation toaccommodate a range of vessel diameters, while having sufficientstructural integrity to maintain their shape and position in theascending aorta when subject to outflow of blood from the leftventricle.

In a preferred embodiment, balloon 330 is further provided with aplurality of folds or pleats 362, shown in FIGS. 27 and 28, which allowthe balloon to be collapsed by evacuation to a small collapsed profilefor introduction into a femoral or iliac artery. In this embodiment,balloon 330 has a blow-up ratio, defined as the ratio of thefully-inflated outside diameter to the deflated outside diameter (beforecollapsing), of about 200%-400%, preferably 300%-400%. Pleats 362 arepreferably at least three in number and each have a width representingapproximately 5-25% of the circumference of the balloon when deflated(but not collapsed by subjecting the interior of the balloon to avacuum). Pleats 362 may be formed into the balloon during theballoon-making process by using a dipping mandrel having longitudinalflutes formed in its periphery. The mandrel is dipped into a containerof liquefied balloon material (e.g. polyurethane) so that a tubularlayer of material solidifies onto the mandrel, conforming to the shapeof the flutes. The mandrel is then removed, producing a pleated balloonof substantially constant thickness. Where a folded, rather thanpleated, balloon is used, the folds may be formed after the balloon ismade by vacuum collapsing the balloon onto a mandrel into the desiredcollapsed profile and heating the balloon, or by expanding the balloonunder pressure and heat in a corrugated mold.

In alternative embodiments, occluding means 328 may comprise any of avariety of structures, including pivot, umbrella or fan-type occlusionmechanisms actuated by pull wire, torque cable, or other type ofmechanical, hydraulic, electric, or shape-memory actuator. Further,occlusion means 328 may comprise multiple occlusion devices arranged intandem on shaft 322; for example, a pair of balloons may be arranged onebehind the other at the distal end of the shaft. In one embodiment, anoccluding balloon is disposed on the shaft to be positionable in theascending aorta, while a seating balloon is disposed distal to theoccluding balloon so as to be positionable in the left ventricle throughthe aortic valve, as described in commonly assigned co-pendingapplication Ser. No. 08/213,760, filed Mar. 16, 1994, the completedisclosure of which is incorporated herein by reference. By inflatingthe seating balloon in the left ventricle, the position of the occludingballoon in the ascending aorta may be maintained against the outflow ofblood from the left ventricle.

Referring again to FIG. 25, a triple-arm adaptor 364 is attached to theproximal end 326 of shaft 322. Triple-arm adaptor 364 includes a workingport 366 in communication with first inner lumen 329 through whichstraightening element 340, guidewire 342, and in some embodiments,surgical or diagnostic instruments may be introduced, as describedbelow. Working port 366 may also be adapted for infusion of fluid suchas cardioplegic fluid, saline or contrast solution, as well as foraspiration of blood, fluids and debris through first inner lumen 329.Triple-arm adaptor 364 further includes an inflation port 368 incommunication with the inflation lumen and configured for connection toan inflation fluid delivery device such as a syringe 370 or othercommercially available balloon-inflation device such as the Indeflator™available from Advanced Cardiovascular Systems, Inc. of Santa Clara,Calif. A pressure measurement port 372 is in communication with thethird lumen (348 or 354) and is adapted for connection to a pressuremeasurement device. Alternatively, where shaft 322 includes only firstinner lumen 329 and inflation lumen 358 as in FIGS. 26B, 28 and 30, port372 may be in communication with first inner lumen 329 and configuredfor pressure measurement, fluid infusion or aspiration.

Referring now to FIGS. 31-33, a preferred embodiment of the method ofthe invention will be described. Initially, a partitioning device 320 ofa size and configuration suitable for the particular patient must beselected. Usually, the patient's aorta will be observed by means of afluoroscopic imaging to determine its size and shape, particularly inthe region of the aortic arch. A partitioning device 320 will beselected having a length sufficient to allow occluding means 328 to beadvanced into the ascending aorta from the point of introduction, whichwill preferably be a femoral or iliac artery in the groin area. Further,a partitioning device will be selected which has a preshaped distalportion 332 with dimensions and shape suitable for positioning thedistal portion in the patient's aortic arch such that distal end 324 isspaced apart from the inner wall of the ascending aorta, preferablyaligned with the center of the aortic arch. Usually, the preshapeddistal portion will have a radius of curvature approximately equal tothat of the aortic arch as measured to the center of the aorta,preferably within a tolerance of about +/−10 mm.

Referring to FIG. 31, partitioning device 320 is preferablysubcutaneously inserted into a femoral or iliac artery 374 in the groinarea using known techniques such as a cut-down or a percutaneoustechnique such as the Seldinger technique. Guidewire 342 is firstintroduced into femoral artery 374 and advanced toward the heart throughiliac artery 376 and aorta 378 so that the distal end of guidewire 342is in the ascending aorta (not shown in FIG. 31). Straightening element340 is inserted into lumen 329 of shaft 322 and positioned in preshapeddistal portion 332 so as to straighten the preshaped distal portion.With balloon 330 deflated, shaft 322 is positioned over guidewire 342,introduced into femoral artery 374 and advanced over guidewire 342through iliac artery 376 and aorta 378. A fluoroscope may be used forvisualization of radiopaque markers 339 on shaft 322 to facilitatepositioning. As an alternative or supplement to fluoroscopic imaging,ultrasonic echocardiography may be used by, for example, positioning anechocardiographic transducer in the esophagus.

As an alternative to femoral or iliac introduction, shaft 322 may beintroduced into carotid artery 387 or brachial artery 389. In suchcases, distal portion 332 of shaft 322 will usually have a generallyS-shaped configuration, as described above with reference to FIG. 25C.Such an S-shaped configuration facilitates positioning balloon 330 inthe ascending aorta with shaft 322 extending superiorly from the aorticarch through brachiocephalic artery 386.

As illustrated in FIGS. 32 and 33, shaft 322 is advanced through aorticarch 380 until balloon 330 resides in ascending aorta 382 betweencoronary ostia 384 and brachiocephalic artery 386. As distal end 324 isadvanced around the aortic arch, straightening element 340 is drawnproximally relative to shaft 322 so as to allow preshaped distal portion332 to conform to the shape of the arch. In an alternative embodiment, arelatively stiff guidewire may be used without a separate straighteningelement, in which case the guidewire may remain in place as shaft 322 isadvanced into the ascending aorta. Straightening element 340 andguidewire 342 may then be removed from shaft 322.

In an alternative technique, partitioning device 320 may be introducedinto the aorta thoracoscopically. In this embodiment, distal end 324 ofshaft 322 may be introduced through a small incision or cannula into thechest cavity. A small penetration is made in the aorta, either in thedescending region or in the aortic arch. Shaft 322 is then inserted intothe aorta using forceps or other thoracoscopic instruments introducedinto the chest cavity through small incisions or cannulae. Such atechnique may be useful where a patient's femoral or iliac arteries areunsuitable for introducing partitioning device 320 percutaneously or bycut down into those vessels.

As illustrated in FIG. 32, once shaft 322 has been positioned so thatballoon 330 is in ascending aorta 382 between coronary ostia 384 andbrachiocephalic artery 386, balloon 330 is expanded by injecting aninflation fluid, usually a saline solution with a radiographic contrastagent, from syringe 370 through inflation port 368. In an exemplaryembodiment, the balloon will be fully inflated in approximately 15-45seconds, depending upon the size of the inflation lumen and theviscosity of the inflation fluid used. In some embodiments, blood may beallowed to flow through inner lumen 329 and directed to cardiopulmonarybypass system 394 (described below), thereby reducing the pressure ofblood flow against balloon 330 during inflation. When fully inflated,the exterior surface of balloon 330 contacts the inner walls of theascending aorta so as to fully occlude the vessel and blocksubstantially all systolic and diastolic blood flow past the balloon.While the heart remains beating, blood may flow from the left ventriclethrough the aortic valve and into the coronary ostia so as to perfusethe myocardium through the coronary arteries. The heart and coronaryarteries are thus isolated from the remainder of the arterial system.

In an alternative embodiment, a gaseous inflation fluid may be used inorder to increase inflation speed. In this way, balloon 330 can be fullyinflated in less time than the period between systolic pulses, reducingthe likelihood that the outflow of blood from the left ventricle duringsystole will displace balloon 330 from its position in the ascendingaorta. Preferably, carbon dioxide is used as the inflation fluid, sincecarbon dioxide, being highly soluble in blood, is unlikely to producepotentially injurious gas emboli in the event of leakage from theballoon. Alternatively, helium may be used. A gas inflation pump andcontrol device similar to those described in U.S. Pat. No. 4,771,765 andU.S. Pat. No. 4,902,272, which are hereby incorporated herein byreference, may be utilized for delivery of pressurized gas throughinflation port 368. The inflation pump may be timed with thecontractions of the heart to facilitate inflation of the balloon betweensystolic pulses. Using such a pump, balloon 330 may be fully inflated inless than about 1 second, and preferably less than about 0.5 second.

FIG. 32 illustrates the components of a system for arresting the heartconstructed in accordance with the principles of the invention. Acardioplegic fluid delivery device 390 is connected to working port 366.A pressure measurement device 392 may be connected to port 372 tomonitor pressure in the ascending aorta upstream of balloon 330 throughthird lumen 348. The patient is placed on a cardiopulmonary bypass (CPB)system 394 to maintain circulation of oxygenated blood throughout thebody. Usually, a venous cannula 396 is positioned in the inferior venacava or right atrium via a femoral vein for withdrawing deoxygenatedblood. In addition, a pulmonary artery venting catheter (described abovewith reference to FIG. 1) may be positioned through the right internaljugular vein or subclavian vein into the pulmonary trunk to withdraw theblood contained therein, thereby decompressing the left atrium. Thewithdrawn blood is delivered to CPB system 394 which removes carbondioxide and oxygenates the blood. The oxygenated blood is then deliveredto a femoral or iliac artery via an arterial cannula 398. A blood filterand recovery system 400 may also be connected to port 366 inpartitioning device 320 via a routing switch 401 to receive blood andother fluids and debris from first inner lumen 329 before or afterdelivery of cardioplegic fluid, filter the blood to remove impurities,and deliver the blood to CPB system 394 for return to the patient'scirculatory system. Further aspects of a CPB system suitable for use inthe system of the invention are described in F. Rossi et al., Long-TermCardiopulmonary Bypass By Peripheral Cannulation in A Model of TotalHeart Failure, Journal of Thoracic and Cardiovascular Surgery (1990),100:914-921; U.S. Pat. No. 4,540,399; and U.S. Pat. No. 5,011,469, whichare all incorporated herein by reference.

With CPB established and balloon 330 blocking blood flow through theascending aorta, the myocardium may then be paralyzed. In a preferredembodiment, a fluid containing cardioplegic agents is delivered bydelivery device 390 through working port 366. The cardioplegic fluidpreferably consists of an aqueous KCl solution mixed with oxygenatedblood at a ratio of four parts blood to one part KCl solution. Theaqueous KCl solution consists of crystalloid KCl mixed with saline tohave a concentration in the range of 10-50 mEq K⁺/liter, preferably15-30 mEq K⁺/liter. Delivery device 390 includes a cooler such as an icebath (not shown) which cools the cardioplegic fluid to e.g. 3° C.-10°C., so as to maintain the heart at a low temperature and to minimizedemand for oxygen. This is usually accomplished without applyingexternal cooling to the heart as is generally applied in conventionalopen cardiac procedures. The cardioplegic fluid is infused into theascending aorta through opening 331 at the distal end of partitioningdevice 320 to maintain a pressure in the aortic root distal to balloon330 sufficient to induce flow of fluid into the coronary arteriesthrough coronary ostia 384. A pressure of about 60-80 mmHg as measuredthrough third lumen 348 is usually sufficient. Cardioplegic fluid ispreferably delivered at a flowrate of about 250-350 ml/min. so as todeliver a total volume of 750-1000 ml in about 2-4 minutes, althoughthis may vary depending upon patient anatomy, physiological changes suchas coronary dilation, and other factors. In pumping the cardioplegicfluid through inner lumen 329, the fluid should be subject to a pumppressure of no more than about 300 mmHg to minimize damage to the bloodcomponent of the mixture. Cardioplegic fluid may also be infused in aretrograde manner through the coronary sinus, by means of a catheter(not shown) positioned transluminally through the right internal jugularvein, as described above. Heart contractions will then cease, withcirculation to the remainder of the patient's body maintained by CPBsystem 394. Cardioplegic fluid flow to the patient's myocardium ismaintained on a periodic basis, e.g., about every 10-20 minutes for 2-4minutes, so long as the myocardium is to remain paralyzed. Acomprehensive description of cardioplegic techniques suitable for use inthe method of the invention is found in Buckberg, Strategies and logicof cardioplegic delivery to prevent, avoid, and reverse ischemic andreperfusion damage, J. Thorac. Cardiovasc. Surg. 1987:93:127-39.

In addition to or instead of infusion of the blood/crystalloidcardioplegic solution, other techniques may be used to arrest heartcontractions. A more concentrated crystalloid KCl solution not mixedwith blood may be delivered through inner lumen 329 at higher pressuresthan with a blood cardioplegic fluid mixture, since without blood in thesolution, there is no risk of hemolysis. This allows inner lumen 329 (aswell as catheter shaft 322) to be of smaller cross-sectional area whilestill providing the necessary flowrate of fluid into the aortic root.However, the above blood cardioplegia technique is presently preferredbecause it is generally believed to provide greater myocardialprotection. In another alternative technique, the patient's body may becooled in a cold-temperature environment or by application of cold-packsto the chest to reduce the temperature of the myocardium sufficiently toinduce fibrillation. The myocardium may be cooled directly by infusionof cold fluid such as cold blood or saline through the coronaryarteries. Alternatively, electrical fibrillation may be accomplished bydelivering electrical signals to the myocardium by means of electrodesplaced on the exterior surface of the heart or externally on the chest.However, cardiac arrest by means of fibrillation is generally lessdesirable than chemical cardioplegic paralysis because there remainssome degree of heart motion which could make surgical intervention moredifficult and because there is a significantly higher demand for oxygen,reducing the safety and duration of the procedure.

Once the heart has been arrested and CPB established, a surgicalprocedure may be performed. The procedure will preferably be aless-invasive procedure performed endovascularly or thoracoscopically.In addition to endovascular aortic valve replacement (described above),the surgical procedures which may be performed using the device andsystem of the invention include repair or replacement of the aortic,mitral and other heart valves, repair of ventricular and atrial septaldefects, septal myotomy, cardiac mapping and ablation to correctarrhythmias, coronary artery bypass grafting, angioplasty, atherectomy,myocardial drilling and revascularization, as well as pulmonary,neurosurgical, and other procedures.

Partitioning device 320 of the present invention is particularlyadvantageous for endovascular introduction of surgical instrumentsthrough the aorta for procedures such as heart valve repair andreplacement. As illustrated in FIG. 33, preshaped distal portion 332 ofshaft 322 conforms to the shape of aortic arch 380 so that opening 331at the distal end is positioned centrally within the ascending aorta andaxially aligned with the center of aortic valve 404. This not onlyenhances infusion of cardioplegic fluid through opening 331, but ensuresthat surgical instruments such as valve cutter 406 introduced throughfirst inner lumen 329 will be aligned with aortic valve 404, either toremove the valve, or to pass through it for intracardiac procedures.Advantageously, soft tip 338 at the distal end of shaft 322 preventsdamage to tissue, particularly the fragile aortic valve leaflets, in theevent of contact therewith.

While being particularly useful in conjunction with minimally-invasivecardiac procedures performed endovascularly and/or thoracoscopically,the partitioning device and system for arresting the heart disclosedherein are also useful in conventional open procedures performed with athoracotomy. Partitioning device 320 may be used where an aorticcross-clamp would pose risks of embolus release due to calcification orother aortic conditions, or in a case of multiple reoperations whereadditional dissection, cross-clamping and cannulation of the aorta maypose serious risks. In open procedures, partitioning device 320 may beintroduced through the femoral or iliac arteries as described above,through the carotid artery 387, through the brachial artery 389, orthrough a penetration in the aorta itself, which is accessible as aresult of the thoracotomy. In such cases, shaft 322 of partitioningdevice 320 may be substantially shorter in length, for example, 20 to 60cm.

Periodically during the procedure, it may be necessary to decompress theleft side of the heart by removing blood and other fluids which haveaccumulated in the aortic root, left atrium and/or left ventricle andwhich have not been removed by the pulmonary artery venting catheter (ifutilized). To remove such fluids, suction may be applied through port366 to the proximal end of inner lumen 329 so as to aspirate fluids fromthe aorta, left ventricle, and or left atrium upstream of balloon 330.Aortic root pressure is usually monitored during this procedure viathird lumen 322. Such venting is usually performed after each periodicinfusion of cardioplegic fluid and additionally as necessary to maintaindecompression of the left side of the heart. In some cases, ventingthrough inner lumen 329 is sufficient to maintain left heartdecompression throughout the procedure, eliminating the need for apulmonary artery venting catheter.

When the procedure has been completed, the heart is restarted bydiscontinuing any flow of cardioplegic fluid through partitioning device320 or retrogradely through the coronary sinus, ventilating the lungs,and perfusing the coronary arteries with warm blood. The region upstreamof balloon 330 may be irrigated by infusing a saline solution throughfirst inner lumen 329. Blood and other fluids upstream of balloon 330may then be aspirated through first inner lumen 329 to remove thrombi,air bubbles, or other emboli which may have been produced during theprocedure, preventing such emboli from entering the brachiocephalic,carotid, or subclavian arteries and reducing the risk of complicationssuch as strokes. Balloon 330 is deflated to allow warm blood fromarterial cannula 398 to flow to the aortic root and through the coronaryostia into the coronary arteries, perfusing the myocardium. Normal heartcontractions may resume promptly, or, if necessary, electricaldefibrillation may be administered to correct heart rhythm. CPB isgradually discontinued, and CPB venous cannula 396 and arterial cannula398 are removed. Partitioning device 320 is withdrawn from the body backthrough the site of entry, and the arterial penetration is closed. Ifthe patient has been put under general anesthesia, the patient is thenbrought from anesthesia to consciousness.

It will be understood by those of skill in the art that variousalternative configurations of endovascular partitioning device 320 arepossible without departing from the scope of the present invention. Onesuch alternative embodiment is illustrated in FIGS. 34A-34B. In thisembodiment, partitioning device 320 has a pull wire 410 disposed in alumen 412 in shaft 322. Pull wire 410 is attached at its distal end toan anchor plate 414 at distal end 324 of shaft 322, preferably offsetfrom the central longitudinal axis of shaft 322. In one embodiment, pullwire 410 extends through a hole in anchor plate 414 and is retainedagainst the anchor plate by a ball 416 fixed to the distal end of pullwire 410. In other respects, device 320 is configured as described abovein connection with FIGS. 25-33, including a balloon 330 mounted to shaft322 near distal end 324, an inflation lumen 418 in communication withthe interior of balloon 330, a soft tip 338 attached to distal end 324of shaft 322, and an inner lumen 329 in communication with distalopening 331. Tension may be applied to the proximal end (not shown) ofpull wire 410 to deflect the distal portion 332 of shaft 322 into ashape suitable for positioning distal portion 332 in the aortic arch (asshown in phantom in FIG. 34A). In an alternative embodiment, an axiallyrigid, laterally-deflectable rod may be used in place of pull wire 410,whereby distal end 324 is deflected by applying a compressive force tothe rod.

In an undeflected configuration (with tension relaxed on pull wire 410),distal portion 332 of the shaft is generally straight. Alternatively,all or part of distal portion 332 may be curved in an undeflectedconfiguration to enhance positionability in the aortic arch. Preferably,a mechanism (not shown) will be provided at the proximal end of shaft322 for applying tension to pull wire 410 and for locking the pull wireto maintain distal portion 332 in a desired shape. Various mechanismsmay be used, such as those described in U.S. Pat. No. 5,030,204, thecomplete disclosure of which is incorporated herein by reference.Usually, shaft 322 is introduced into an artery in a generally straightconfiguration, and tension is applied to pull wire 410 to deflect distalportion 332 as the shaft is advanced into the aortic arch. Once distalportion 332 is positioned in the aortic arch, tension on pull wire 410is adjusted so as to position distal end 324 radially within theascending aorta so as to be spaced apart from the inner wall of theaorta and axially aligned with the center of the aortic valve. Pull wire410 is then locked in tension to maintain distal portion 332 in itsdeflected configuration.

A further alternative embodiment of partitioning device 320 isillustrated in FIGS. 35A-35B. In this embodiment, shaft 322 ispositionable in an interior lumen 420 of a guiding catheter 422. Device320 may be configured as described above with reference to FIGS. 25-30,including balloon 330 near distal end 324, inner lumen 329, inflationlumen 346, pressure lumen 348, soft tip 338 attached to distal end 324,and triple-arm adaptor 364 attached to proximal end 326. Guidingcatheter 422 has a proximal end 424 and a distal end 426, with axiallumen 420 extending therebetween. A soft tip (not shown) may be attachedto distal end 426 to minimize injury to the aorta or aortic valve in theevent of contact therewith. A proximal adaptor 428 is attached toproximal end 424, and has a first port 430 in communication with lumen420 through which shaft 322 may be introduced, and a second port 432 incommunication with lumen 420 for infusing or aspirating fluid. Port 430may further include a hemostasis valve. Guiding catheter 422 also has adistal portion 434 which is either preshaped or deflectable into a shapegenerally conforming to the shape of the aortic arch. Techniquessuitable for preshaping or deflecting distal portion 434 of guidingcatheter 422 are described above in connection with FIGS. 25-30 and34A-34B. In an exemplary embodiment, guiding catheter 422 is preshapedin a generally U-shaped configuration, with a radius of curvature in therange of 20-80 mm. In this embodiment, a stylet (not shown) like thatdescribed above in connection with FIGS. 25-30 is provided forstraightening distal portion 434 for purposes of percutaneouslyintroducing guiding catheter 422 into an artery.

In use, guiding catheter 422 is introduced into an artery, e.g. afemoral or iliac artery, and advanced toward the heart until distal end426 is in the ascending aorta. A guidewire (not shown) may be used toenhance tracking. Where a stylet is used to straighten a preshapedguiding catheter for subcutaneous introduction, the stylet is withdrawnas preshaped distal portion 434 is advanced through the aortic arch.Once guiding catheter 422 is in position, shaft 322 may be introducedthrough port 430 and lumen 420 and advanced toward the heart untilballoon 330 is disposed between the coronary ostia and thebrachiocephalic artery, distal to the distal end 426 of guiding catheter422. The distal portion 332 of shaft 322 (FIG. 25) is shaped to conformto the aortic arch by preshaped portion 434 of guiding catheter 422.Balloon 330 is then inflated to fully occlude the ascending aorta andblock blood flow therethrough.

In yet another embodiment, shown in FIGS. 36A-36B, partitioning device320 includes a shaping element 440 positionable in a lumen in shaft 322,such as third inner lumen 348. Shaping element 440 has a proximal end442, a distal end 444 and a preshaped distal portion 446. Preshapeddistal portion 446 may be generally U-shaped as illustrated, or may havean angular, “S”-shaped or other configuration in an unstressedcondition, which will shape distal portion 332 to generally conform toat least a portion of the patient's aortic arch. Shaping element 440 ispreferably stainless steel, nickel titanium alloy, or otherbiocompatible material with a bending stiffness greater than that ofshaft 322 so as to deflect distal portion 332 into the desired shape.Shaping element 440 may be a guidewire over which shaft 322 is advancedto the ascending aorta, or a stylet which is inserted into third innerlumen 348 after shaft 322 is positioned with balloon 330 in theascending aorta. In a preferred embodiment, shaping element 440 isconfigured to position distal end 324 of shaft 322 in a radial positionwithin the ascending aorta to be spaced apart from the interior wallthereof, and in particular, axially aligned with the center of theaortic valve.

In a further aspect of the invention, illustrated in FIGS. 37A-37E,partitioning device 320 is coupled to an arterial bypass cannula 450 soas to allow both device 320 and cannula 450 to be introduced through thesame arterial puncture. Arterial bypass cannula 450 is configured forconnection to a cardiopulmonary bypass system for delivering oxygenatedblood to the patient's arterial system. Arterial bypass cannula 450 hasa distal end 452, a proximal end 454, a blood flow lumen 456 extendingbetween proximal end 454 and distal end 452, and an outflow port 458 atdistal end 452. A plurality of additional outflow ports 460 may beprovided along the length of arterial bypass cannula 450, particularlynear distal end 452. In a preferred embodiment, arterial bypass cannula450 has a length between about 10 cm and 60 cm, and preferably betweenabout 15 cm and 30 cm.

An adaptor 462 is connected to proximal end 454 of bypass cannula 450,and includes a first access port 464 and a second access port 466, bothin fluid communication with blood flow lumen 456. Access port 466 isconfigured for fluid connection to tubing from a cardiopulmonary bypasssystem, and preferably has a barbed fitting 468. Access port 464 isconfigured to receive partitioning device 320 therethrough. Preferably,a hemostasis valve 470, shown in FIGS. 37C and 37E, is mounted in accessport 464 to prevent leakage of blood and other fluids through accessport 464 whether or not shaft 322 of partitioning device 320 ispositioned therein. Hemostasis valve 470 may have any number ofwell-known constructions, including, for example, an elastomeric disk469 having one or more slits 472 through which shaft 422 may bepositioned, and a diaphragm 471 adjacent to the disk with a central hole474 for sealing around the periphery of shaft 322. A hemostasis valve ofthis type is described in U.S. Pat. No. 4,000,739, which is incorporatedherein by reference. Other types of hemostasis valves may also be used,such as duck-bill valves, O-ring seals, and rotational or slidingmechanical valves. In addition, a Touhy-Borst valve 473 including athreaded, rotatable cap 475 may be provided on the proximal end ofaccess port 464 to facilitate clamping and sealing around shaft 322 bytightening cap 475, which compresses O-rings 477 about shaft 322.

Shaft 322 of partitioning device 320 and blood flow lumen 456 of bypasscannula 450 are configured and dimensioned to facilitate sufficientblood flow through blood flow lumen 456 to support full cardiopulmonarybypass with complete cessation of cardiac activity, without anundesirable level of hemolysis. In a preferred embodiment, arterialbypass cannula 450 has an outer diameter of 6 mm to 10 mm, and bloodflow lumen 456 has an inner diameter of 5 mm to 9 mm. Shaft 322 ofpartitioning device 320 has an outer diameter in the range of 2 mm to 5mm. In this way, blood flow lumen 456, with shaft 322 positionedtherein, facilitates a blood flow rate of at least about 4 liters/minuteat a pump pressure of less than about 250 mmHg.

Arterial bypass cannula 450 is preferably introduced into an artery,usually a femoral artery, with partitioning device 320 removed fromblood flow lumen 456. An obturator 476, illustrated in FIG. 37D, may bepositioned in blood flow lumen 456 such that the tapered distal end 478of obturator 476 extends distally from the distal end 452 of arterialbypass cannula 450. The arterial bypass cannula 450 may be introducedinto the artery by various techniques including percutaneous methodssuch as the Seldinger technique, but is usually of sufficient size torequire a surgical cutdown. A guidewire 480 may be slidably positionedthrough a lumen 482 in obturator 476 to facilitate introduction ofarterial bypass cannula 450. Guidewire 480 is advanced into the arterythrough an arteriotomy, and arterial bypass cannula 450 with obturator476 positioned therein is advanced into the artery over guidewire 480.Obturator 476 may then be removed, allowing partitioning device 320 tobe introduced into the artery through blood flow lumen 456, usually overguidewire 480. Guidewire 480 may be advanced toward the heart and intothe ascending aorta to facilitate positioning the distal end 324 ofpartitioning device 320 therein.

In an alternative embodiment, arterial bypass cannula 450 may beconfigured so that partitioning device 320 is not removable from bloodflow lumen 456. In this embodiment, bypass cannula 450 is introducedinto an artery with partitioning device 320 positioned in blood flowlumen 456. Partitioning device 320 may be slidable within a limitedrange of movement within blood flow lumen 456. Alternatively,partitioning device 320 may be fixed to arterial bypass cannula 450 toprevent relative movement between the two. For example, shaft 322 may beextruded from the same tubing which is used to form arterial bypasscannula 450. Or, shaft 322 may be attached within the interior of bloodflow lumen 456 or at the distal end 452 of arterial bypass cannula 450.Additionally, distal end 452 of bypass cannula 450 may be tapered toseal around shaft 322 and may or may not be bonded to shaft 322. In thisconfiguration, side ports 460 permit outflow of blood from blood flowlumen 456.

A further embodiment of an interventional device constructed inaccordance with the principles of the invention is illustrated in FIGS.38A-38F. In this embodiment, a cardiac venting device 480 is providedfor withdrawing blood from the interior of the heart to preventdistension of the myocardium during cardiopulmonary bypass. Cardiacventing device 480 includes a venous bypass cannula 482 having a distalend 484 and a proximal end 486. A blood flow lumen 488, shown in FIGS.38B and 38F, extends between distal end 484 and proximal end 486. Aninflow port 490 in fluid communication with blood flow lumen 488 isdisposed at distal end 484. A plurality of additional inflow ports 492may be provided in venous bypass cannula 482 near distal end 484. Anadaptor 494 is mounted to proximal end 486 and includes a first accessport 496 and a second access port 498 both in fluid communication withblood flow lumen 488. Access port 498 is configured for connection to atube from a cardiopulmonary bypass system, and preferably includes abarbed fitting 500. Access port 496 is configured to receive a ventingcatheter 502 therethrough, and preferably includes a hemostasis valve504, shown in FIG. 38C. Hemostasis valve 504 may have a constructionlike that of hemostasis valve 470 described above in connection withFIG. 37C.

Venting catheter 502 includes an elongated flexible shaft 506 having adistal end 508 and a proximal end 510. An inner lumen 512, shown inFIGS. 38B and 38F, extends from proximal end 510 to distal end 508, andis in fluid communication with an inflow port 514 in distal end 508.Additional side inflow ports as shown in FIG. 38F may also be providednear distal end 508. In one embodiment, as shown in FIG. 38A, aninflatable balloon 516 may be provided near distal end 508 proximal todistal port 514. An inflation lumen 518 extending through shaft 506 isin fluid communication with the interior of balloon 516 for deliveringan inflation fluid thereto. Balloon 516 may be used to facilitateplacement in the pulmonary artery, to facilitate measurement of wedgepressure in the pulmonary artery, or for other purposes. Additionally, apressure lumen 520 may be provided in shaft 506, with a pressure port522 at distal end 508 in fluid communication with pressure lumen 520.This facilitates pressure sensing at distal end 508. A triple armadaptor 524 is mounted to proximal end 510 of shaft 506. Adaptor 524 hasa first access port 526 in fluid communication with inner lumen 512, asecond access port 528 in fluid communication with balloon inflationlumen 518, and a third access port 530 in fluid communication withpressure lumen 520.

Blood flow lumen 488 and shaft 506 are dimensioned and configured tofacilitate adequate blood flow through blood flow lumen 488 to supportfull cardiopulmonary bypass with complete cessation of cardiac activity,without an undesirable level of hemolysis. In a preferred embodiment,venous bypass cannula 482 has an outer diameter of 6 mm to 12 mm, whileblood flow lumen 488 has an inner diameter of 5 mm to 11.5 mm. Shaft 506of venting catheter 502 preferably has an outer diameter between about 3mm and 4 mm. Such a configuration facilitates a blood flow rate throughblood flow lumen 488 of at least about 4 liters/minute at a vacuum pumppressure no less than about −75 mmHg.

The distal portion of venous bypass cannula 482 may be straight as shownin FIG. 38A, or, alternatively, may have a pre-shaped curvature as shownin FIG. 38D. Such a curved configuration may be advantageous in order toguide venting catheter 502 from the right atrium into the rightventricle through the tricuspid valve, as described more fully below. Avariety of curves, from a 180_semi-circle, as shown in FIG. 38D, to acurve of 90_ or less may be provided, according to the direction inwhich it is desired to guide venting catheter 502. An obturator 532 maybe provided for straightening the distal portion for introduction ofvenous bypass cannula 482. Obturator 532 has a stiffness which isgreater than that of the distal portion of venous bypass cannula 482such that positioning obturator 532 in blood flow lumen 488 straightensthe distal portion of bypass cannula 482. Obturator 532 may be providedwith an inner lumen 534 through which a movable guidewire 536 may bepositioned to facilitate introduction into the patient's venous system.

Cardiac venting device 480 may be introduced using various techniques,but, as with arterial bypass cannula 450 described above, willordinarily require a surgical cutdown. Usually, venous bypass cannula482 is introduced into a vein, preferably a femoral vein or internaljugular vein, without venting catheter 502 positioned in blood flowlumen 488. Obturator 532 may be positioned within blood flow lumen 488to facilitate introduction. Preferably, venous bypass cannula 482 has alength of at least about 75 cm to allow the distal end 484 to bepositioned near or within the right atrium of the heart via the inferiorvena cava from a femoral vein. Alternatively, venous bypass cannula 482may have a length of about 50 cm to 70 cm to facilitate introductionthrough the internal jugular vein in the patient's neck and positioningof distal end 484 in the superior vena cava and/or right atrium. Oncevenous bypass cannula 482 is in position, venting catheter 502 may beintroduced through access port 496 and blood flow lumen 488 until distalend 508 is within the patient's heart. Venting catheter 502 may then beadvanced until distal end 508 is in the desired portion of the heart towithdraw blood therefrom. Venting catheter 502 preferably has a lengthof at least about 110 cm to reach from a femoral vein to the pulmonaryartery, or a length of about 70 cm to 90 cm to reach from the internaljugular vein to the pulmonary artery.

Alternative embodiments of cardiac venting device 480 are illustrated inFIGS. 39A-39D. In the embodiment of FIG. 39A, venous bypass cannula 482comprises a non-tapered proximal portion 540 and a tapered distalportion 542. Blood flow lumen 488 extends from proximal end 486 todistal end 543. Inflow ports 492 are in fluid communication with bloodflow lumen 488 as above. Non-tapered proximal portion 540 preferably hasa length selected to allow inflow ports 492 to be positioned within theright atrium of the heart or in the inferior vena cava near the heart. Adistal inflow port 544 and side inflow ports 546 are provided at thedistal end 543. Distal inflow port 544 and side inflow ports 546 arealso in fluid communication with blood flow lumen 488. Additional sideinflow ports may be provided over the entire length of tapered section542. A balloon (not shown) may also be provided at distal end 543, alongwith a pressure port (not shown), and associated lumens, as provided inprevious embodiments. An adaptor 548 is attached to proximal end 486.Adaptor 548 may include an arm 550, preferably having a barbed fittingfor connection to a tube from a cardiopulmonary bypass system. Otheraccess ports may be provided in adapter 548 for balloon inflation andpressure measurement.

The total length of venous bypass cannula 482, including proximalportion 540 and tapered distal portion 542, is preferably at least 110cm to reach the pulmonary artery from a femoral vein, or at least about70 cm to 90 cm to reach the pulmonary artery from the internal jugularvein.

Tapered portion 542 may be tapered from an outer diameter of 6 mm-11 mmto an outer diameter of 3 mm-5 mm at distal end 543, so as to providethe flexibility and small profile necessary for positioning distal end543 within the pulmonary artery, while maintaining a sufficiently largeblood flow lumen 488 to support full cardiopulmonary bypass with cardiacfunction arrested.

In yet another embodiment, illustrated in FIGS. 39C and 39D, a shaft 506of venting catheter 502 has a proximal end 552 which is attached todistal end 484 of venous bypass cannula 482. Shaft 506 has a distal end554, an inner lumen 556 (FIG. 39D), and a distal port 558 in fluidcommunication with inner lumen 556 at distal end 554. A plurality ofadditional ports 560 may be provided along shaft 506 near distal end554. Proximal end 552 of shaft 506 is attached to venous bypass cannula482 by means of a frame 562, illustrated in FIG. 39D. Shaft 506 may bealigned coaxially with venous bypass cannula 482, or offset in aneccentric configuration. Inner lumen 556 is in fluid communication withblood flow lumen 488 in venous bypass cannula 482. In this way, bloodwithdrawn through distal ports 558, 560 in venting catheter 502 flowsinto blood flow lumen 488, along with blood withdrawn through inflowports 490, 492. The proximal end of the device has a configurationsuitable for connecting blood flow lumen 488 to a cardiopulmonary bypasssystem, and may include an adaptor like adaptor 548 illustrated in FIG.39A.

Referring now to FIG. 40, the use of the devices illustrated in FIGS.37-39 will be described. Arterial bypass cannula 450 is positioned infemoral artery 374, usually by surgical cutdown, with obturator 476positioned in blood flow lumen 456. Guidewire 480 is first advancedthrough an arteriotomy into femoral artery 374, and arterial bypasscannula 450 along with obturator 476 are advanced over guidewire 480into the artery. Obturator 476 may then be removed from blood flow lumen456. Access port 466 on adaptor 462 is connected to the oxygenated bloodoutlet of cardiopulmonary bypass system 394.

Venous bypass cannula 482 is introduced into femoral vein 570, usuallyon the same side of the patient as femoral artery 374 in which arterialbypass cannula 450 is introduced. In this way, the same surgical cutdownmay be used for introduction of both devices. Venous bypass cannula 482will usually be introduced over a guidewire 536 as described above, andmay have obturator 532 positioned in blood flow lumen 488 to facilitateintroduction. If venous bypass cannula 482 includes a shaped distalportion as shown in FIG. 38D, obturator 532 may be used to straightenthe distal portion for introduction. Venous bypass cannula 482 isadvanced through the femoral vein, iliac vein and inferior vena cava574. Preferably, venous bypass cannula 482 is positioned so that thedistal port 490 is within the right atrium 576. Inflow ports 492 willthen be positioned within the right atrium 576 and/or within theinferior vena cava 574 near right atrium 576.

Cardiopulmonary bypass may then be initiated. Cardiopulmonary bypasssystem 394 receives deoxygenated blood from the patient's venous systemthrough blood flow lumen 488 of venous bypass cannula 480, oxygenatesthe blood, and returns the oxygenated blood to blood flow lumen 456 ofarterial bypass cannula 450.

Venting catheter 502 is then introduced through access port 496 intoblood flow lumen 488. Venting catheter 502 is advanced toward the heartthrough blood flow lumen 488, and through distal port 490 into the rightatrium 576. The venting catheter may be positioned in various locationswithin the heart, however, in a preferred embodiment, venting catheter502 is positioned such that distal port 514 is within the pulmonaryartery 578. Usually, this will be accomplished by positioning aSwan-Ganz catheter through blood flow lumen 488 and into right atrium576 before introducing venting catheter 502. Usually, a balloon on thedistal end of the Swan-Ganz catheter is inflated within the rightatrium, and the distal end of the Swan-Ganz catheter is advanced fromthe right atrium 576, through the right ventricle 580, and into thepulmonary artery 578. Once the Swan-Ganz catheter has been positioned inthe pulmonary artery, the balloon at its distal end may be deflated, andventing catheter 502 is advanced over the Swan-Ganz catheter until thedistal end 508 of venting catheter 502 is within the pulmonary artery.The Swan-Ganz catheter may then be removed from the patient.

Access port 526 at the proximal end of venting catheter 502 is connectedto a deoxygenated blood inlet of cardiopulmonary bypass system 394.Venting catheter 502 withdraws blood from the pulmonary artery 578 anddelivers the blood to cardiopulmonary bypass system 394. Alternatively,access port 526 may be connected to a separate roller pump (not shown)which feeds the blood withdrawn from the heart into filter/recoveryreservoir 400, then returns the blood to CPB system 394. If a balloon516 is provided at the distal end of venting catheter 502, a ballooninflation device, such as a syringe 582, is connected to access port528, and inflation fluid is injected into balloon 516. A pressuremeasurement device 590 is connected to access port 530 for monitoringthe pressure within the pulmonary artery through pressure port 522.

Cardiac function may then be arrested. Guidewire 480 may be advancedthrough arterial bypass cannula 450 until its distal end is in ascendingaorta 380. Partitioning device 320 may then be introduced through bloodflow lumen 456 into femoral artery 374 and advanced toward the heartuntil balloon 330 is disposed in the ascending aorta betweenbrachiocephalic artery 386 and coronary ostia 384. Guidewire 480 maythen be removed. If partitioning device 320 has a preshaped distalportion 332, an obturator as described above may be used forstraightening distal portion 332 during introduction. Occlusion balloon330 of partitioning device 320 is expanded to occlude ascending aorta382. Cardioplegic fluid is delivered through inner lumen 329 ofpartitioning device 320 into ascending aorta 382 upstream of occlusionballoon 330, from which the cardioplegic fluid flows into the coronaryarteries to perfuse the myocardium. As described above in reference toFIG. 32, a cooled mixture of blood and a KCl/saline solution infused ata rate of about 300 ml/min. at no more than 300 mmHg is the presentlypreferred technique of inducing cardioplegia. Cardioplegic fluid mayalso be infused in a retrograde manner through the coronary sinus, aspreviously described. The myocardium is quickly paralyzed, and cardiacfunction ceases. Cardiopulmonary bypass system 394 maintains peripheralcirculation of oxygenated blood through venous bypass cannula 482 andarterial bypass cannula 450. As described above in reference to FIG. 32,it may be necessary to periodically vent the left side of the heart ofblood and other fluids not removed by pulmonary artery venting catheter502. To accomplish this, suction may be applied through working port 366to withdraw fluids from the left atrium, left ventricle, and aortic rootthrough inner lumen 329, from which the fluids may be passed tofilter/recovery unit 400 and cardiopulmonary bypass system 394 foroxygenation and return to the patient's arterial system. Aortic rootpressure is monitored during the procedure through third lumen 348.

The patient is thus prepared for a cardiovascular surgical procedurewith the heart arrested and cardiopulmonary bypass established, allthrough a single arterial puncture and a single venous puncture, withoutany incisions in the chest. Preferably, minimally-invasive surgicaltechniques are then utilized to perform the surgical procedure, whichmay be any of a number of cardiac, vascular, pulmonary, or neurosurgicalprocedures.

Following surgery, the patient's heart is restarted by discontinuing anyflow of cardioplegic fluid through partitioning device 320 orretrogradely through the coronary sinus, ventilating the lungs, andperfusing the coronary arteries with warm blood. The region upstream ofballoon 330 may first be irrigated by infusing a saline solution throughfirst inner lumen 329. Blood and other fluids upstream of balloon 330may then be aspirated through first inner lumen 329 to remove thrombi,air bubbles, or other emboli which may have been produced during theprocedure, preventing such emboli from entering the brachiocephalic,carotid, or subclavian arteries and reducing the risk of complicationssuch as strokes. Balloon 330 is deflated to allow warm blood fromarterial bypass cannula 450 to flow through the ascending aorta to thecoronary arteries, perfusing the myocardium. Normal heart contractionsmay resume promptly, or, if necessary, electrical defibrillation may beadministered to correct heart rhythm. Partitioning device 320 iswithdrawn from the body back through arterial bypass cannula 450.Venting catheter 502 is withdrawn from the pulmonary artery (firstdeflating balloon 516, if inflated) and out of the body back throughvenous bypass cannula 482. CPB is gradually discontinued, and venousbypass cannula 482 and arterial bypass cannula 450 are removed. Arterialand venous punctures or cut-downs are closed. If the patient has beenput under general anesthesia, the patient is then brought fromanesthesia to consciousness.

It will be understood to those of skill in the art that a variety ofdevices may be introduced through blood flow lumen 456 of arterialbypass cannula 450 or through blood flow lumen 488 of venous bypasscannula 482 instead of aortic partitioning device 322 and cardiacventing catheter 502. For example, coronary angioplasty or atherectomycatheters may be introduced through arterial bypass cannula 450 andadvanced into the coronary arteries, facilitating CPB assist duringangioplasty and atherectomy procedures through a single femoral arterialpenetration. A catheter for retroperfusion of cardioplegic fluid fromthe coronary sinus may be introduced through venous cannula 482 fromeither the internal jugular vein, subclavian vein, or a femoral veininto the heart and into the coronary sinus. Electrophysiology cathetersfor myocardial mapping and ablation may be introduced through arterialbypass cannula 450 or venous bypass cannula 482 and advanced into theheart or coronary arteries to facilitate CPB assist during suchprocedures without an additional femoral arterial or venous penetration.A variety of endovascular instruments for inspecting and treating theheart and great vessels, including angioscopes, valve repair devices,valve removal devices, devices for introduction and attachment of valveprostheses, septal defect repair devices, aneurysm treatment devices,vascular stents, staplers, shunts or grafts to facilitate coronaryartery bypass grafting, and other devices may be introduced througharterial bypass cannula 450 or venous bypass cannula 482, facilitatingCPB assist during such interventional procedures without requiringadditional arterial or venous penetrations.

The devices and methods disclosed herein offer significant advantagesover conventional techniques. Important among these advantages is theability to establish cardiopulmonary bypass and perform interventionalprocedures within the heart and great vessels with a minimum of venousand arterial penetrations, thereby reducing substantially the morbidityand mortality of such procedures. Further, the invention facilitatesperforming such interventional procedures and establishingcardiopulmonary bypass through a single arterial penetration and asingle venous penetration. In this way, the invention not only reducesthe total number of penetrations and the associated trauma and risksattendant such penetrations, but allows a greater number of patients toreceive closed-chest surgical treatment who, because of conditions inone or more femoral vessels, would otherwise be prevented from receivingsuch treatment.

The invention further facilitates arresting cardiac function andestablishing cardiopulmonary bypass by means of an endovascular deviceintroduced through a single femoral arterial penetration, eliminatingthe need for a conventional gross thoracotomy. By obviating the need toopen the chest for external clamping of the aorta, the inventionfacilitates the performance of a new generation of minimally-invasivecardiac and vascular procedures. Elimination of a median sternotomy orgross thoracotomy in such procedures produces lower mortality andmorbidity, reduced patient suffering, decreased hospitalization andrecovery time, and reduced medical costs. Moreover, the invention isuseful even in open-chest procedures as a substitute for the aorticcross-clamp where calcification or other conditions could make externalaortic clamping undesirable.

While the present invention has been described herein in terms ofcertain preferred embodiments, it will be apparent to one of ordinaryskill in the art that many modifications and improvements can be made tothe invention without departing from the scope thereof.

1. A cardiopulmonary bypass catheter system for arresting a patient'sheart and maintaining arterial circulation comprising: a return cannulahaving an elongated cannula body, a distal end adapted for positioningin a blood vessel, a proximal end, a return lumen in the cannula bodyadapted for flowing blood therethrough, a return outlet at the distalend in communication with the return lumen, a return inlet at theproximal end in communication with the return lumen, a catheter port atthe proximal end in communication with the return lumen and adapted toremovably receive a catheter therein, and a hemostasis valve in thecatheter port adapted to seal around a catheter positioned in thecatheter port; and an occlusion catheter slidably positioned through thecatheter port and the return lumen, the occlusion catheter having aninfusion lumen with an infusion inlet and an infusion outlet, theinfusion inlet being adapted for connection to a source of cardioplegicfluid, and an expandable occlusion member attached to the occlusioncatheter at a location proximal to the infusion outlet having acollapsed configuration adapted for introduction through the returnlumen and an expanded configuration adapted for occlusion of theascending aorta between the coronary ostia and the brachiocephalicartery; wherein the return lumen is adapted to deliver blood when theocclusion catheter is positioned therein at a flow rate sufficient tomaintain arterial circulation when the heart is arrested.
 2. Thecardiopulmonary bypass catheter system of claim 1 further comprising aventing port in communication with the infusion lumen, the venting portbeing adapted for connection to a pump for withdrawing fluids from theascending aorta through the infusion lumen.
 3. The cardiopulmonarybypass catheter system of claim 1 wherein the return lumen is adapted todeliver blood at a flow rate of at least about 4 l/min and a pressure ofless than about 250 mm Hg.
 4. The cardiopulmonary bypass catheter systemof claim 1 wherein the return lumen has an inner diameter of about 5-9mm.
 5. The cardiopulmonary bypass catheter system of claim 4 wherein theocclusion catheter has an outer diameter of about 2-5 mm.
 6. Thecardiopulmonary bypass catheter system of claim 1 further comprising asource of cardioplegic fluid coupled to the infusion port.
 7. Thecardiopulmonary bypass catheter system of claim 1 further comprising asource of oxygenated blood coupled to the infusion port.
 8. Thecardiopulmonary bypass catheter system of claim 1 further comprising apump coupled to the return inlet adapted for pumping oxygenated bloodthrough the return lumen.
 9. The cardiopulmonary bypass catheter systemof claim 8 wherein the pump is adapted to pump oxygenated blood throughthe return lumen at a rate of at least about 4 l/min, at a pressure ofless than about 250 mm Hg with the occlusion catheter positioned in thereturn lumen.
 10. The cardiopulmonary bypass catheter system of claim 1wherein the infusion lumen is configured to deliver cardioplegic fluidat a rate of at least 250 ml/min at a pressure of less than about 300 mmHg.
 11. The cardiopulmonary bypass catheter system of claim 10 whereinthe infusion lumen has a cross-sectional area of at least about 4.5 mm².12. The cardiopulmonary bypass catheter system of claim 1 furthercomprising a venous cannula positionable in a vein and an oxygenatorfluidly coupled to the venous cannula, the oxygenator being fluidlycoupled to the return inlet.
 13. The cardiopulmonary bypass cathetersystem of claim 1 wherein the return cannula is positionable in afemoral artery and the occlusion catheter has a length of at least about80 cm such that the occlusion member is positionable in the ascendingaorta.
 14. The cardiopulmonary bypass catheter system of claim 1 whereinthe occlusion catheter has a pre-shaped distal portion configured toconform to at least a portion of the aortic arch.
 15. Thecardiopulmonary bypass catheter system of claim 1 wherein the occlusioncatheter has a pressure lumen with a pressure outlet distal to theocclusion member and a pressure port proximal to the occlusion memberadapted for connection to a pressure monitoring device.
 16. Acardiopulmonary bypass catheter system for arresting a patient's heartand maintaining arterial circulation comprising: a return cannula havingan elongated cannula body, a distal end adapted for positioning in ablood vessel, a proximal end, a return lumen in the cannula body adaptedfor flowing blood therethrough, a return outlet at the distal end incommunication with the return lumen, a return inlet at the proximal endin communication with the return lumen, a catheter port at the proximalend in communication with the return lumen and adapted to removablyreceive a catheter therein, and a hemostasis valve in the catheter portadapted to seal around a catheter positioned in the catheter port; anocclusion catheter slidably positioned through the catheter port and thereturn lumen, the occlusion catheter having an infusion lumen with aninfusion inlet and an infusion outlet, a venting port in communicationwith the infusion lumen, and an expandable occlusion member attached tothe occlusion catheter at a location proximal to the infusion outlethaving a collapsed configuration adapted for introduction through thereturn lumen and an expanded configuration adapted for occlusion of theascending aorta between the coronary ostia and the brachiocephalicartery; a return pump coupled to the return inlet and adapted forpumping oxygenated blood through the return lumen with the occlusioncatheter positioned therein at a flow rate sufficient to maintainarterial circulation with the heart arrested; a source of cardioplegicfluid coupled to the infusion port; and a venting pump coupled to theventing port for withdrawing fluids from the ascending aorta through theinfusion lumen.
 17. A cardiopulmonary bypass catheter system,comprising: a cannula having a return lumen adapted for flowing bloodtherethrough, the return lumen having a return outlet; and an occlusioncatheter sized and configured to be slidably positioned through thelumen, the occlusion catheter having an occlusion member, the occlusionmember having a collapsed configuration adapted for introduction throughthe return lumen and an expanded configuration adapted for occlusion ofthe ascending aorta between the coronary ostia and the brachiocephalicartery; wherein the return lumen is configured to deliver blood via thereturn outlet at a flow rate sufficient to maintain arterial circulationwhen the heart is arrested and when at least a portion of the occlusioncatheter is positioned therein.
 18. The cardiopulmonary bypass cathetersystem of claim 17, comprising: a catheter part at the proximal end ofthe return cannula in communication with the return lumen and adapted toremovably receive the occlusion catheter therein, and a hemostasis valvein the catheter port adapted to seal around the occlusion catheter whenthe occlusion catheter is positioned in the catheter port.
 19. Thecardiopulmonary bypass catheter system of claim 17, wherein theocclusion catheter has an infusion lumen having an infusion outletlocated distal to the occlusion member.
 20. The cardiopulmonary bypasscatheter system of claim 17, wherein the return lumen has an innerdiameter of about 5-9 mm.
 21. The cardiopulmonary bypass catheter systemof claim 17, wherein the occlusion catheter is sized such that theocclusion member is located within the ascending aorta between thecoronary ostia and the brachiocephalic artery, when the cannula isintroduced into an artery peripheral to the aorta.
 22. Thecardiopulmonary bypass catheter system of claim 17, wherein theocclusion member is configured to occlude the aorta when the occlusionmember is in the expanded configuration.
 23. A cardiopulmonary bypasscatheter system comprising; an occlusion catheter having an occlusionmember, the occlusion member having a collapsed configuration adaptedfor introduction through the return lumen and an expanded configurationadapted for occlusion of the ascending aorta between the coronary ostiaand the brachiocephalic artery; a cannula having means for deliveringblood at a flow rate sufficient to maintain arterial circulation whenthe heart is arrested and when at least a portion of the occlusioncatheter is disposed within the means; and wherein the occlusioncatheter is sized and configured to be slidably positioned through themeans.